A wiki is a website
A website, also written as Web site, web site, or simply site, is a collection of related web pages containing images, videos or other digital assets. A website is hosted on at least one web server, accessible via a network such as the Internet or a private local area network through an Internet...

 that allows the creation and editing of any number of interlinked web page
Web page
A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...

s via a web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

 using a simplified markup language
Markup language
A markup language is a modern system for annotating a text in a way that is syntactically distinguishable from that text. The idea and terminology evolved from the "marking up" of manuscripts, i.e. the revision instructions by editors, traditionally written with a blue pencil on authors' manuscripts...

WYSIWYG is an acronym for What You See Is What You Get. The term is used in computing to describe a system in which content displayed onscreen during editing appears in a form closely corresponding to its appearance when printed or displayed as a finished product...

 text editor. Wikis are typically powered by wiki software
Wiki software
Wiki software is collaborative software that runs a wiki, i.e., a website that allows users to create and collaboratively edit web pages via a web browser. A wiki system is usually a web application that runs on one or more web servers...

 and are often used collaboratively
Collaborative software
Collaborative software is computer software designed to help people involved in a common task achieve goals...

 by multiple users. Examples include community websites, corporate intranet
An intranet is a computer network that uses Internet Protocol technology to securely share any part of an organization's information or network operating system within that organization. The term is used in contrast to internet, a network between organizations, and instead refers to a network...

s, knowledge management
Knowledge management
Knowledge management comprises a range of strategies and practices used in an organization to identify, create, represent, distribute, and enable adoption of insights and experiences...

 systems, and note services. The software can also be used for personal notetaking.

Wikis may serve many different purposes. Some permit control over different functions (levels of access). For example, editing rights may permit changing, adding or removing material. Others may permit access without enforcing access control. Other rules may also be imposed for organizing content.

Ward Cunningham
Ward Cunningham
Howard G. "Ward" Cunningham is an American computer programmer who developed the first wiki. A pioneer in both design patterns and Extreme Programming, he started programming the software WikiWikiWeb in 1994 and installed it on the website of his software consultancy, Cunningham & Cunningham , on...

, the developer of the first wiki software, WikiWikiWeb
WikiWikiWeb is a term that has been used to refer to four things: the first wiki, or user-editable website, launched on 25 March 1995 by Ward Cunningham as part of the Portland Pattern Repository ; the Perl-based application that was used to run it, also developed by Cunningham, which was the first...

, originally described it as "the simplest online database that could possibly work." "Wiki" is a Hawaiian
Hawaiian language
The Hawaiian language is a Polynesian language that takes its name from Hawaii, the largest island in the tropical North Pacific archipelago where it developed. Hawaiian, along with English, is an official language of the state of Hawaii...

 word meaning "fast" or "quick".


WikiWikiWeb was the first wiki. Ward Cunningham started developing WikiWikiWeb in Portland, Oregon, in 1994, and installed it on the Internet domain
Domain name
A domain name is an identification string that defines a realm of administrative autonomy, authority, or control in the Internet. Domain names are formed by the rules and procedures of the Domain Name System .... on March 25, 1995. It was named by Cunningham, who remembered a Honolulu International Airport
Honolulu International Airport
Honolulu International Airport is the principal aviation gateway of the City & County of Honolulu and the State of Hawaii and is identified as one of the busiest airports in the United States, with traffic now exceeding 21 million passengers a year and rising.It is located in the Honolulu...

 counter employee telling him to take the "Wiki Wiki Shuttle
Wiki Wiki Shuttle
The Wiki Wiki Shuttle is a zero-fare shuttle bus system at the Honolulu International Airport. Shuttles run between 6:00 AM and 10:00 PM, carrying people and baggage between the various terminals....

" bus that runs between the airport's terminals. According to Cunningham, "I chose wiki-wiki as an alliterative substitute for 'quick' and thereby avoided naming this stuff quick-web."

Cunningham was in part inspired by Apple's HyperCard
HyperCard is an application program created by Bill Atkinson for Apple Computer, Inc. that was among the first successful hypermedia systems before the World Wide Web. It combines database capabilities with a graphical, flexible, user-modifiable interface. HyperCard also features HyperTalk, written...

. Apple had designed a system allowing users to create virtual "card stacks" supporting links among the various cards. Cunningham developed Vannevar Bush's
Vannevar Bush
Vannevar Bush was an American engineer and science administrator known for his work on analog computing, his political role in the development of the atomic bomb as a primary organizer of the Manhattan Project, the founding of Raytheon, and the idea of the memex, an adjustable microfilm viewer...

 ideas by allowing users to "comment on and change one another's text."

In the early 2000s, wikis were increasingly adopted in enterprise as collaborative software. Common uses included project communication, intranets, and documentation, initially for technical users. Today some companies use wikis as their only collaborative software and as a replacement for static intranets, and some schools and universities use wikis to enhance group learning. There may be greater use of wikis behind firewalls
Firewall (computing)
A firewall is a device or set of devices designed to permit or deny network transmissions based upon a set of rules and is frequently used to protect networks from unauthorized access while permitting legitimate communications to pass....

 than on the public Internet.

On March 15, 2007, wiki entered the online Oxford English Dictionary
Oxford English Dictionary
The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...



Ward Cunningham and co-author Bo Leuf
Bo Leuf
Bo Arne Leuf was the author of the book The Wiki Way , written in collaboration with WikiWiki inventor Ward Cunningham. His book Peer To Peer discusses different P2P solutions both from a technical and legal point of view.Bo Leuf lived in Gothenburg, Sweden...

, in their book The Wiki Way: Quick Collaboration on the Web
The Wiki Way
The Wiki Way: Quick Collaboration on the Web is a 2001 book about wikis by Bo Leuf and Ward Cunningham. It was the first major book published about using wikis. Cunningham is the inventor of wikis, having created WikiWikiWeb, the first wiki website software...

, described the essence of the Wiki concept as follows:
  • A wiki invites all users to edit any page or to create new pages within the wiki Web site, using only a plain-vanilla
    Vanilla software
    Vanilla software is computer software that is not customized from its delivered form - i.e. it is used without any customizations applied to it...

     Web browser without any extra add-ons
    Browser extension
    A browser extension is a computer program that extends the functionality of a web browser in some way. Depending on the browser and the version, the term may be distinct from similar terms such as plug-in or add-on. Mozilla Firefox was designed with the idea of being a small and simple web browser,...

  • Wiki promotes meaningful topic associations between different pages by making page link creation almost intuitively easy and showing whether an intended target page exists or not.
  • A wiki is not a carefully crafted site for casual visitors. Instead, it seeks to involve the visitor in an ongoing process of creation and collaboration that constantly changes the Web site landscape.

A wiki enables communities to write documents collaboratively, using a simple markup language and a web browser. A single page in a wiki website is referred to as a "wiki page", while the entire collection of pages, which are usually well interconnected by hyperlink
In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...

s, is "the wiki". A wiki is essentially a database for creating, browsing, and searching through information. A wiki allows for non-linear, evolving, complex and networked text, argument and interaction.

A defining characteristic of wiki technology is the ease with which pages can be created and updated. Generally, there is no review before modifications are accepted. Many wikis are open to alteration by the general public without requiring them to register user
User (computing)
A user is an agent, either a human agent or software agent, who uses a computer or network service. A user often has a user account and is identified by a username , screen name , nickname , or handle, which is derived from the identical Citizen's Band radio term.Users are...

 accounts. Many edits can be made in real-time and appear almost instantly online. This can facilitate abuse of the system. Private wiki servers require user authentication
Authentication is the act of confirming the truth of an attribute of a datum or entity...

 to edit pages, and sometimes even to read them.

Maged N. Kamel Boulos
Maged N. Kamel Boulos
Maged N. Kamel Boulos is a British health informatician and scientist currently based at the University of Plymouth, having worked before that at the University of Bath and at City University London. He is particularly known for his research into Geographic Information Systems applications in...

, Cito Maramba and Steve Wheeler
Steve Wheeler
Steve Wheeler is a British academic, author, speaker and learning technologist.- Early life :Wheeler was born in Devonport, a suburb of Plymouth, England...

 write that it is the "openness of wikis that gives rise to the concept of 'Darwikinism', which is a concept that describes the 'socially Darwinian process' that wiki pages are subject to. Basically, because of the openness and rapidity that wiki pages can be edited, the pages undergo a natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

 process like that which nature subjects to living organisms. 'Unfit' sentences and sections are ruthlessly culled, edited and replaced if they are not considered 'fit', which hopefully results in the evolution of a higher quality and more relevant page. Whilst such openness may invite 'vandalism' and the posting of untrue information, this same openness also makes it possible to rapidly correct or restore a 'quality' wiki page."

Editing wiki pages

There are many different ways in which wikis have users edit the content. Ordinarily, the structure and formatting of wiki pages are specified with a simplified markup language, sometimes known as wikitext
Wikitext language, or wiki markup, is a lightweight markup language used to write pages in wiki websites, such as Wikipedia, and is a simplified alternative/intermediate to HTML. Its ultimate purpose is to be converted by wiki software into HTML, which in turn is served to web browsers.There is no...

 (for example, starting a line of text with an asterisk
An asterisk is a typographical symbol or glyph. It is so called because it resembles a conventional image of a star. Computer scientists and mathematicians often pronounce it as star...

 often sets up a bulleted list
Bullet (typography)
In typography, a bullet is a typographical symbol or glyph used to introduce items in a list. For example:*Item 1*Item 2*Item 3...

). The style and syntax of wikitexts can vary greatly among wiki implementations, some of which also allow HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

 tags. Designers of wikis often take this approach because HTML, with its many cryptic tags, is not very legible, making it hard to edit. Wikis therefore favour plain-text editing, with fewer and simpler conventions than HTML, for indicating style and structure. Although limiting access to HTML and Cascading Style Sheets
Cascading Style Sheets
Cascading Style Sheets is a style sheet language used to describe the presentation semantics of a document written in a markup language...

 (CSS) of wikis limits user ability to alter the structure and formatting of wiki content, there are some benefits. Limited access to CSS promotes consistency in the look and feel, and having JavaScript
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....

 disabled prevents a user from implementing code that may limit access for other users.
MediaWiki is a popular free web-based wiki software application. Developed by the Wikimedia Foundation, it is used to run all of its projects, including Wikipedia, Wiktionary and Wikinews. Numerous other wikis around the world also use it to power their websites...

Equivalent HTML Rendered output
"Take some more tea
Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...

," the March Hare said to Alice, very earnestly.

"I've had nothing yet," Alice replied in an offended tone, "so I can't take more."

"You mean you can't take ''less''?" said the Hatter. "It's very easy to take ''more'' than nothing."
<p>"Take some more tea," the March Hare said to Alice, very earnestly.</p>

<p>"I've had <b>nothing</b> yet," Alice replied in an offended tone, "so I can't take more."</p>

<p>"You mean you can't take <i>less</i>?" said the Hatter. "It's very easy to take <i>more</i> than nothing."</p>

"Take some more tea
Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...

," the March Hare said to Alice, very earnestly.

"I've had nothing yet," Alice replied in an offended tone, "so I can't take more."

"You mean you can't take less?" said the Hatter. "It's very easy to take more than nothing."

Increasingly, wikis are making WYSIWYG
WYSIWYG is an acronym for What You See Is What You Get. The term is used in computing to describe a system in which content displayed onscreen during editing appears in a form closely corresponding to its appearance when printed or displayed as a finished product...

 editing available to users, usually by means of JavaScript
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....

 or an ActiveX
ActiveX is a framework for defining reusable software components in a programming language-independent way. Software applications can then be composed from one or more of these components in order to provide their functionality....

 control that translates graphically entered formatting instructions into the corresponding HTML tags
HTML element
An HTML element is an individual component of an HTML document. HTML documents are composed of a tree of HTML elements and other nodes, such as text nodes. Each element can have attributes specified. Elements can also have content, including other elements and text. HTML elements represent...

 or wikitext. In those implementations, the markup of a newly edited, marked-up version of the page is generated and submitted to the server transparently, shielding the user from this technical detail. However, WYSIWYG controls do not always provide all of the features available in wikitext, and some users prefer not to use a WYSIWYG editor. Hence, many of these sites offer some means to edit the wikitext directly.

Most wikis keep a record of changes made to wiki pages; often, every version of the page is stored. This means that authors can revert to an older version of the page, should it be necessary because a mistake has been made or the page has been vandalized. Many implementations, like MediaWiki
MediaWiki is a popular free web-based wiki software application. Developed by the Wikimedia Foundation, it is used to run all of its projects, including Wikipedia, Wiktionary and Wikinews. Numerous other wikis around the world also use it to power their websites...

, allow users to supply an edit summary when they edit a page; this is a short piece of text summarising the changes. It is not inserted into the article, but is stored along with that revision of the page, allowing users to explain what has been done and why; this is similar to a log message when making changes to a revision-control
Revision control
Revision control, also known as version control and source control , is the management of changes to documents, programs, and other information stored as computer files. It is most commonly used in software development, where a team of people may change the same files...



Within the text of most pages there are usually a large number of hypertext
Hypertext is text displayed on a computer or other electronic device with references to other text that the reader can immediately access, usually by a mouse click or keypress sequence. Apart from running text, hypertext may contain tables, images and other presentational devices. Hypertext is the...

 links to other pages. This form of non-linear navigation is more "native" to wiki than structured/formalized navigation schemes. That said, users can also create any number of index or table-of-contents pages, with hierarchical categorization or whatever form of organization they like. These may be challenging to maintain by hand, as multiple authors create and delete pages in an ad hoc manner. Wikis generally provide one or more ways to categorize or tag pages to support the maintenance of such index pages.

Most wikis have a backlink
Backlinks, also known as incoming links, inbound links, inlinks, and inward links, are incoming links to a website or web page...

 feature, which displays all pages that link to a given page.

It is typical in a wiki to create links to pages that do not yet exist, as a way to invite others to share what they know about a subject new to the wiki.

Linking and creating pages

Links are created using a specific syntax, the so-called "link pattern" (also see CURIE
A CURIE defines a generic, abbreviated syntax for expressing URIs. It is an abbreviated URI expressed in CURIE syntax, and may be found in both XML and non-XML grammars...

). Originally, most wikis used CamelCase
CamelCase , also known as medial capitals, is the practice of writing compound words or phrases in which the elements are joined without spaces, with each element's initial letter capitalized within the compound and the first letter either upper or lower case—as in "LaBelle", "BackColor",...

 to name pages and create links. These are produced by capitalizing words in a phrase and removing the spaces between them (the word "CamelCase" is itself an example). While CamelCase makes linking very easy, it also leads to links which are written in a form that deviates from the standard spelling. CamelCase-based wikis are instantly recognizable because they have many links with names such as "TableOfContents" and "BeginnerQuestions." It is possible for a wiki to render the visible anchor for such links "pretty" by reinserting spaces, and possibly also reverting to lower case. However, this reprocessing of the link to improve the readability of the anchor is limited by the loss of capitalization information caused by CamelCase reversal. For example, "RichardWagner" should be rendered as "Richard Wagner," whereas "PopularMusic" should be rendered as "popular music". There is no easy way to determine which capital letters should remain capitalized. As a result, many wikis now have "free linking" using brackets, and some disable CamelCase by default.


Wiki software is a type of collaborative software
Collaborative software
Collaborative software is computer software designed to help people involved in a common task achieve goals...

 that runs a wiki system, allowing web pages to be created and edited using a common web browser. It is usually implemented as an application server
Application server
An application server is a software framework that provides an environment in which applications can run, no matter what the applications are or what they do...

 that runs on one or more web server
Web server
Web server can refer to either the hardware or the software that helps to deliver content that can be accessed through the Internet....

s. The content is stored in a file system
File system
A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...

, and changes to the content are stored in a relational database management system
Relational database management system
A relational database management system is a database management system that is based on the relational model as introduced by E. F. Codd. Most popular databases currently in use are based on the relational database model....

. A commonly implemented software package is MediaWiki
MediaWiki is a popular free web-based wiki software application. Developed by the Wikimedia Foundation, it is used to run all of its projects, including Wikipedia, Wiktionary and Wikinews. Numerous other wikis around the world also use it to power their websites...

, which runs this encyclopedia. See the List of wiki software for further information.

Alternatively, personal wiki
Personal wiki
A personal wiki is a wiki maintained primarily for personal use. Personal wikis allow people to organize information on their desktop or mobile computing devices in a manner similar to community wikis, but without the need for collaboration by multiple users....

s run as a standalone application on a single computer. WikidPad
WikidPad is an open source, Python-based wiki-like outliner for storing thoughts, ideas, to-do lists, contacts, and other notes with wiki-like linking between pages....

 is an example. Or even single local HTML file with JavaScript inside - like TiddlyWiki
TiddlyWiki is an open source single page application wiki. A single HTML file contains CSS, JavaScript, and the content. The content is divided into a series of sections, or Tiddlers. A user is encouraged to read a TiddlyWiki by following links rather than sequentially scrolling down the...


Wikis can also be created on a "wiki farm
Wiki farm
A wiki hosting service or wiki farm is a server or an array of servers that offer users tools to simplify the creation and development of individual, independent wikis...

", where the server side software is implemented by the wiki farm owner. PBwiki
PBworks is a commercial real-time collaborative editing system created by David Weekly, with Ramit Sethi and Nathan Schmidt joining shortly thereafter as co-founders. Based in San Mateo, California, the company's original name stems from their belief that "making a wiki is as easy as making a...

, Socialtext
Socialtext Incorporated is a company based in Palo Alto, California that produces enterprise social software, comprising an integrated suite of web-based social software applications including microblogging, user profile, directories, groups, personal dashboards using OpenSocial widgets, and shared...

, Wetpaint
Wetpaint is a Seattle, Washington-based company, founded in 2005, that hosts both user-generated and professionally created content. Wetpaint began as a wiki farm, hosting wikis using their own proprietary software. In 2010, the main site was rebranded as Wetpaint Entertainment, a website focused...

, and Wikia
Wikia is a free web hosting service for wikis . It is normally free of charge for readers and editors, deriving most of its income from advertising, and publishes all user-provided text under copyleft licenses. Wikia hosts several hundred thousand wikis using the open-source wiki software MediaWiki...

 are popular examples of such services. Some wiki farms can also make private, password-protected wikis. Note that free wiki farms generally contain advertising on every page. For more information, see Comparison of wiki farms
Comparison of wiki farms
This comparison of wiki farms details notable online services which host wiki-style editable web pages. General characteristics of cost, presence of advertising, licensing, and Alexa rank are compared, as are technical differences in editing, features, wiki engine, multilingual support and syntax...


Controlling changes

Wikis are generally designed with the philosophy of making it easy to correct mistakes, rather than making it difficult to make them. Thus, while wikis are very open, they provide a means to verify the validity of recent additions to the body of pages. The most prominent, on almost every wiki, is the "Recent Changes" page—a specific list numbering recent edits, or a list of edits made within a given time frame. Some wikis can filter the list to remove minor edits and edits made by automatic importing scripts ("bots
Internet bot
Internet bots, also known as web robots, WWW robots or simply bots, are software applications that run automated tasks over the Internet. Typically, bots perform tasks that are both simple and structurally repetitive, at a much higher rate than would be possible for a human alone...


From the change log, other functions are accessible in most wikis: the revision history
A changelog is a log or record of changes made to a project, such as a website or software project, usually including such records as bug fixes, new features, etc...

 shows previous page versions and the diff
In computing, diff is a file comparison utility that outputs the differences between two files. It is typically used to show the changes between one version of a file and a former version of the same file. Diff displays the changes made per line for text files. Modern implementations also...

 feature highlights the changes between two revisions. Using the revision history, an editor can view and restore a previous version of the article. The diff feature can be used to decide whether or not this is necessary. A regular wiki user can view the diff of an edit listed on the "Recent Changes" page and, if it is an unacceptable edit, consult the history, restoring a previous revision; this process is more or less streamlined, depending on the wiki software used.

In case unacceptable edits are missed on the "recent changes" page, some wiki engines provide additional content control. It can be monitored to ensure that a page, or a set of pages, keeps its quality. A person willing to maintain pages will be warned of modifications to the pages, allowing him or her to verify the validity of new editions quickly. A watchlist is a common implementation of this.

Some wikis also implement "patrolled revisions," in which editors with the requisite credentials can mark some edits as not vandalism. A "flagged revisions" system can prevent edits from going live until they have been reviewed.


Most wikis offer at least a title search
Search algorithm
In computer science, a search algorithm is an algorithm for finding an item with specified properties among a collection of items. The items may be stored individually as records in a database; or may be elements of a search space defined by a mathematical formula or procedure, such as the roots...

, and sometimes a full-text search
Full text search
In text retrieval, full text search refers to techniques for searching a single computer-stored document or a collection in a full text database...

. The scalability of the search depends on whether the wiki engine uses a database. Some wikis, such as PmWiki
PmWiki is wiki software written by Patrick R. Michaud in the PHP programming language. It is free software, licensed under the terms of the GNU General Public License.-Design focus:...

, use flat files. MediaWiki's first versions used flat files, but it was rewritten by Lee Daniel Crocker in the early 2000s to be a database application. Indexed database access is necessary for high speed searches on large wikis. Alternatively, external search engines
Web search engine
A web search engine is designed to search for information on the World Wide Web and FTP servers. The search results are generally presented in a list of results often referred to as SERPS, or "search engine results pages". The information may consist of web pages, images, information and other...

 such as Google Search
Google search
Google or Google Web Search is a web search engine owned by Google Inc. Google Search is the most-used search engine on the World Wide Web, receiving several hundred million queries each day through its various services....

 can sometimes be used on wikis with limited searching functions in order to obtain more precise results. However, a search engine's indexes can be very out of date (days, weeks or months) for many websites.


Critics of publicly editable wiki systems argue that these systems could be easily tampered with, while proponents argue that the community of users can catch malicious content and correct it. Lars Aronsson, a data systems specialist, summarizes the controversy as follows:
High editorial standards in medicine have led to the idea of expert-moderated wikis. Some wikis allow one to link to specific versions of articles, which has been useful to the scientific community, in that expert peer reviewers could analyse articles, improve them and provide links to the trusted version of that article.

Noveck points out that "participants are accredited by members of the wiki community, who have a vested interest in preserving the quality of the work product, on the basis of their ongoing participation." On controversial topics that have been subject to disruptive editing, a wiki may restrict editing to registered users.


The open philosophy of most wikis, allowing anyone to edit content, does not ensure that every editor is well-meaning. Vandalism can be a major problem. In larger wiki sites, such as those run by the Wikimedia Foundation
Wikimedia Foundation
Wikimedia Foundation, Inc. is an American non-profit charitable organization headquartered in San Francisco, California, United States, and organized under the laws of the state of Florida, where it was initially based...

, vandalism
Vandalism is the behaviour attributed originally to the Vandals, by the Romans, in respect of culture: ruthless destruction or spoiling of anything beautiful or venerable...

 can go unnoticed for a period of time. Wikis by their very nature are susceptible to intentional disruption, known as "trolling
Troll (Internet)
In Internet slang, a troll is someone who posts inflammatory, extraneous, or off-topic messages in an online community, such as an online discussion forum, chat room, or blog, with the primary intent of provoking readers into an emotional response...

Wikis tend to take a soft security
Soft security
Soft security usually refers to security which protects something from harm in quiet and unobtrusive ways, often invisibly and after the fact, rather than with visible barriers before the fact...

approach to the problem of vandalism; making damage easy to undo rather than attempting to prevent damage. Larger wikis often employ sophisticated methods, such as bots that automatically identify and revert vandalism and JavaScript enhancements that show characters that have been added in each edit. In this way vandalism can be limited to just "minor vandalism" or "sneaky vandalism", where the characters added/eliminated are so few that bots do not identify them and users do not pay much attention to them.

The amount of vandalism a wiki receives depends on how open the wiki is. For instance, some wikis allow unregistered users, identified by their IP address
IP address
An Internet Protocol address is a numerical label assigned to each device participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing...

es, to edit content, whilst others limit this function to just registered users. Most wikis allow anonymous editing without an account, but give registered users additional editing functions; on most wikis, becoming a registered user is a short and simple process. Some wikis require an additional waiting period before gaining access to certain tools. For example, on the English Wikipedia
English Wikipedia
The English Wikipedia is the English-language edition of the free online encyclopedia Wikipedia. Founded on 15 January 2001 and reaching three million articles by August 2009, it was the first edition of Wikipedia and remains the largest, with almost three times as many articles as the next...

, registered users can only rename pages if their account is at least four days old. Other wikis such as the Portuguese Wikipedia
Portuguese Wikipedia
The Portuguese Wikipedia is a Portuguese language edition of Wikipedia , the free encyclopedia. It was the fifth edition of Wikipedia, started in June 2001. It is currently the tenth largest Wikipedia by article count, containing articles.From late 2004, the edition grew rapidly...

 use an editing requirement instead of a time requirement, granting extra tools after the user has made a certain number of edits to prove their trustworthiness and usefulness as an editor. Basically, "closed up" wikis are more secure and reliable but grow slowly, whilst more open wikis grow at a steady rate but result in being an easy target for vandalism. A clear example of this would be that of Wikipedia and Citizendium
Citizendium is an English-language wiki-based free encyclopedia project launched by Larry Sanger, who co-founded Wikipedia in 2001....

. The first is extremely open, allowing anyone with a computer and internet access to edit it, making it grow rapidly, whilst the latter requires the users' real name and a biography
A biography is a detailed description or account of someone's life. More than a list of basic facts , biography also portrays the subject's experience of those events...

 of themselves, affecting the growth of the wiki but creating an almost "vandalism-free" ambiance.

Malware, short for malicious software, consists of programming that is designed to disrupt or deny operation, gather information that leads to loss of privacy or exploitation, or gain unauthorized access to system resources, or that otherwise exhibits abusive behavior...

 can also be problem, as users can add links to sites hosting malicious code. For example, a German Wikipedia article about the Blaster Worm was edited to include a hyperlink to a website that would infect the user's computer. A countermeasure is the use of software that prevents users from saving an edit that contains a link to a site listed on a blacklist
A blacklist is a list or register of entities who, for one reason or another, are being denied a particular privilege, service, mobility, access or recognition. As a verb, to blacklist can mean to deny someone work in a particular field, or to ostracize a person from a certain social circle...

 of malware sites.

Wiki software must also block JavaScript or other kinds of scripting that the attacker may attempt to insert directly into the page during editing sessions.

Edit war
Edit war
An edit war or revert war is a situation that sometimes arises on websites which are run on wiki principles, such as Wikipedia, where users repeatedly re-edit or undo or reverse the prior user's edits in an attempt to make their own preferred version of a page visible...

s can also occur as users repetitively revert a page to the version they favor. Some wiki software allows an administrator to stop such edit wars by locking a page from further editing until a decision has been made on what version of the page would be most appropriate. For example, an article named Dolf was deemed not notable
Notability is the property of being worthy of notice, having fame, or being considered to be of a high degree of interest, significance, or distinction...

 and after debate
Debate or debating is a method of interactive and representational argument. Debate is a broader form of argument than logical argument, which only examines consistency from axiom, and factual argument, which only examines what is or isn't the case or rhetoric which is a technique of persuasion...

 between several users a new article on a more general topic was created called Dart Golf
Dart golf
Dart Golf games are games in which darts are thrown at traditional dart boards or dart boards that resemble golf courses with colored areas that represent a golf course. Dart golf games use golf-like rules and scoring...


Some wikis are in a better position than others to control behavior due to governance structures existing outside the wiki. For instance, a college teacher can create incentives for students to behave themselves on a class wiki he administers, by limiting editing to logged-in users and pointing out that all contributions can be traced back to the contributors. Bad behavior can then be dealt with in accordance with university policies.


Many wiki communities are private, particularly within enterprises
A company is a form of business organization. It is an association or collection of individual real persons and/or other companies, who each provide some form of capital. This group has a common purpose or focus and an aim of gaining profits. This collection, group or association of persons can be...

. They are often used as internal documentation
Internal documentation
Computer software is said to have Internal Documentation if the notes on how and why various parts of code operate is included within the source code as comments...

 for in-house systems and applications. Some companies use wikis to allow customers to help produce software documentation. A study of corporate wiki users found that they could be divided into "synthesizers" and "adders" of content. Synthesizers' frequency of contribution was affected more by their impact on other wiki users, while adders' contribution frequency was affected more by being able to accomplish their immediate work. In 2005, the Gartner Group, noting the increasing popularity of wikis, estimated that they would become mainstream collaboration tools in at least 50% of companies by 2009.

Wikis have also been used in the academic community for sharing and dissemination of information across institutional and international boundaries. In those settings, they have been found useful for collaboration on grant writing
Grant writing
Grant writing refers to the practice of completing an application processes for funding provided by an institution such as a government department, corporation, foundation or trust. Such application processes are often referred to as either grant "proposals" or "submissions". Successful grant...

, strategic planning
Strategic planning
Strategic planning is an organization's process of defining its strategy, or direction, and making decisions on allocating its resources to pursue this strategy. In order to determine the direction of the organization, it is necessary to understand its current position and the possible avenues...

, departmental documentation, and committee work. In the mid-2000s, the increasing trend amongst industries toward collaboration was placing a heavier impetus upon educators to make students proficient in collaborative work, inspiring even greater interest in wikis being used in the classroom.

Wikis have found some use within the legal profession, and within government. Examples include the Central Intelligence Agency
Central Intelligence Agency
The Central Intelligence Agency is a civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence, responsible for providing national security intelligence assessment to senior United States policymakers...

's Intellipedia
Intellipedia is an online system for collaborative data sharing used by the United States Intelligence Community . It was established as a pilot project in late 2005 and formally announced in April 2006 and consists of three wikis running on JWICS, SIPRNet, and Intelink-U...

, designed to share and collect intelligence, dKospedia, which was used by the American Civil Liberties Union
American Civil Liberties Union
The American Civil Liberties Union is a U.S. non-profit organization whose stated mission is "to defend and preserve the individual rights and liberties guaranteed to every person in this country by the Constitution and laws of the United States." It works through litigation, legislation, and...

 to assist with review of documents pertaining to internment of detainees in Guantánamo Bay; and the wiki of the United States Court of Appeals for the Seventh Circuit
United States Court of Appeals for the Seventh Circuit
The United States Court of Appeals for the Seventh Circuit is a federal court with appellate jurisdiction over the courts in the following districts:* Central District of Illinois* Northern District of Illinois...

, used to post court rules and allow practitioners to comment and ask questions. The United States Patent and Trademark Office
United States Patent and Trademark Office
The United States Patent and Trademark Office is an agency in the United States Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.The USPTO is based in Alexandria, Virginia,...

 uses a wiki to allow the public to collaborate on finding prior art
Prior art
Prior art , in most systems of patent law, constitutes all information that has been made available to the public in any form before a given date that might be relevant to a patent's claims of originality...

 relevant to examination of pending patent applications. Queens
Queens is the easternmost of the five boroughs of New York City. The largest borough in area and the second-largest in population, it is coextensive with Queens County, an administrative division of New York state, in the United States....

, New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

 has used a wiki to allow citizens to collaborate on the design and planning of a local park. Cornell Law School
Cornell Law School
Cornell Law School, located in Ithaca, New York, is a graduate school of Cornell University and one of the five Ivy League law schools. The school confers three law degrees...

 founded a wiki-based legal dictionary called Wex, whose growth has been hampered by restrictions on who can edit.

There also exist WikiNodes which are pages on wikis that describe related wikis. They are usually organized as neighbors and delegates. A neighbor wiki is simply a wiki that may discuss similar content or may otherwise be of interest. A delegate wiki is a wiki that agrees to have certain content delegated to that wiki.

One way of finding a wiki on a specific subject is to follow the wiki-node network from wiki to wiki; another is to take a Wiki "bus tour", for example: . Domain names
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...

 containing "wiki" are growing in popularity to support specific niches.

The English Wikipedia has the largest user base among wikis on the World Wide Web
World Wide Web
The World Wide Web is a system of interlinked hypertext documents accessed via the Internet...

 and ranks in the top 10 among all Web sites in terms of traffic. Other large wikis include the WikiWikiWeb, Memory Alpha
Memory Alpha
Memory Alpha is a wiki that is an encyclopedic reference for topics related to the Star Trek fictional universe. Conceived by Harry Doddema and Dan Carlson in September 2003 and officially launched on December 5 of that year, it uses the wiki model and is hosted by Wikia, Inc. on the MediaWiki...

, Wikitravel
-External links:* *...

, World66 and was a Swedish language wiki, started in October 2001 by Lars Aronsson . In its first three years , ran as an open wiki that anyone could edit...

, a Swedish-language knowledge base.

Medical and health-related wiki examples include Ganfyd
Ganfyd is a medical wiki community and online medical wiki encyclopedia, created in November 2005 by a group of doctors working in the United Kingdom. The site has been the subject of academic exposition into emerging methods of disseminating medical information and more specifically, the...

, an online collaborative medical reference that is edited by medical professionals and invited non-medical experts.

The four basic types of users who participate in wikis are reader, author, wiki administrator and web administrator. The web administrator is responsible for installation and maintenance of the wiki engine and the container web server. The wiki administrator maintains wiki content and is
provided additional functions pertaining to pages (e.g. page protection and deletion), and can adjust users' access rights by, for instance, blocking them from editing.

A study of several hundred wikis showed that a relatively high number of administrators for a given content size is likely to reduce growth; that access controls restricting editing to registered users tends to reduce growth; that a lack of such access controls tends to fuel new user registration; and that higher administration ratios (i.e. admins/user) have no significant effect on content or population growth.


Conferences and meetings about wikis in general include:
  • The International Symposium on Wikis (WikiSym
    WikiSym is a short hand for International Symposium on Wikis and Open Collaboration, or the Wiki Symposium, a conference dedicated to wiki research and practice. Its proceedings are published in the ACM Digital Library.-Overview:...

    ), a conference
    Academic conference
    An academic conference or symposium is a conference for researchers to present and discuss their work. Together with academic or scientific journals, conferences provide an important channel for exchange of information between researchers.-Overview:Conferences are usually composed of various...

     dedicated to wiki research
    Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...

     and practice in general.
  • RecentChangesCamp
    RecentChangesCamp is an unconference focused on wikis, that was first held in 2006. It is named after the "recent changes" feature that is found in most wikis...

    , an unconference
    An unconference is a participant-driven meeting. The term "unconference" has been applied, or self-applied, to a wide range of gatherings that try to avoid one or more aspects of a conventional conference, such as high fees, sponsored presentations, and top-down organization...

     on wiki-related topics

Conferences on specific wiki sites and applications include:
  • Atlassian Summit, an annual conference for users of Atlassian
    Atlassian is a software company based in Sydney, Australia which makes business enterprise software, targeted at software developers. On 1 September 2010, the World Economic Forum announced the company as a Technology Pioneer for 2011.- Products :...

     software, including Confluence
    Confluence (software)
    Confluence is an enterprise wiki software. Written in Java and mainly used in corporate environments, Confluence is developed and marketed by Atlassian. Confluence is sold as either on-premises software or as a hosted solution...

  • RegioWikiCamp, a semi-annual unconference on "regiowikis", or wikis for cities and other geographic areas.
  • SMWCon, a bi-annual conference for users and developers of Semantic MediaWiki
    Semantic MediaWiki
    Semantic MediaWiki is an extension to MediaWiki that allows for annotating semantic data within wiki pages, thus turning a wiki that incorporates the extension into a semantic wiki...

  • TikiFest, a frequently held meeting for users and developers of Tiki Wiki CMS Groupware.
  • Wikimania
    Wikimania is an annual international conference for users of the wiki projects operated by the Wikimedia Foundation...

    , an annual conference dedicated to the research and practice of Wikimedia Foundation
    Wikimedia Foundation
    Wikimedia Foundation, Inc. is an American non-profit charitable organization headquartered in San Francisco, California, United States, and organized under the laws of the state of Florida, where it was initially based...

     projects like Wikipedia.


Wikis typically have a set of rules governing user behavior. Wikipedia, for instance, has an intricate set of policies and guidelines summed up in its five pillars: Wikipedia is an encyclopedia; Wikipedia has a neutral point of view; Wikipedia is free content; Wikipedians should interact in a respectful and civil manner; and Wikipedia does not have firm rules. Many wikis have adopted a set of commandments. For instance, Conservapedia
Conservapedia is an English-language wiki project written from a self-described American conservative Christian point of view. The website considers itself to be a supporter of "conservative, family-friendly" content...

 commands, among other things, that its editors use "B.C." rather than "B.C.E." when referring to years prior to the common era and refrain from "unproductive activity." One teacher instituted a commandment for a class wiki, "Wiki unto others as you would have them wiki unto you."

Legal environment

Joint authorship of articles, in which different users participate in correcting, editing, and compiling the finished product, can also cause editors to become tenants in common of the copyright, making it impossible to republish without the permission of all co-owners, some of whose identities may be unknown due to pseudonymous or anonymous editing. However, where persons contribute to a collective work such as an encyclopedia, there is no joint ownership if the contributions are separate and distinguishable. Despite most wikis' tracking of individual contributions, the action of contributing to a wiki page is still arguably one of jointly correcting, editing, or compiling which would give rise to joint ownership.

Some copyright issues can be alleviated through the use of an open content
Open content
Open content or OpenContent is a neologism coined by David Wiley in 1998 which describes a creative work that others can copy or modify. The term evokes open source, which is a related concept in software....

 license. Version 2 of the GNU Free Documentation License
GNU Free Documentation License
The GNU Free Documentation License is a copyleft license for free documentation, designed by the Free Software Foundation for the GNU Project. It is similar to the GNU General Public License, giving readers the rights to copy, redistribute, and modify a work and requires all copies and...

 includes a specific provision for wiki relicensing; Creative Commons
Creative Commons
Creative Commons is a non-profit organization headquartered in Mountain View, California, United States devoted to expanding the range of creative works available for others to build upon legally and to share. The organization has released several copyright-licenses known as Creative Commons...

 licenses are also popular. When no license is specified, an implied license to read and add content to a wiki may be deemed to exist on the grounds of business necessity and the inherent nature of a wiki, although the legal basis for such an implied license may not exist in all circumstances.

Wikis and their users can be held liable for certain activities that occur on the wiki. If a wiki owner displays indifference and forgoes controls (such as banning copyright infringers) that he could have exercised to stop copyright infringement, he may be deemed to have authorized infringement, especially if the wiki is primarily used to infringe copyrights or obtains direct financial benefit, such as advertising revenue, from infringing activities. In the United States, wikis may benefit from Section 230 of the Communications Decency Act
Communications Decency Act
The Communications Decency Act of 1996 was the first notable attempt by the United States Congress to regulate pornographic material on the Internet. In 1997, in the landmark cyberlaw case of Reno v. ACLU, the United States Supreme Court struck the anti-indecency provisions of the Act.The Act was...

, which protects sites that engage in "Good Samaritan" policing of harmful material, with no requirement on the quality or quantity of such self-policing. However, it has also been argued that a wiki's enforcement of certain rules, such as anti-bias, verifiability, reliable sourcing, and no-original-research policies, could pose legal risks. When defamation occurs on a wiki, theoretically all users of the wiki can be held liable, because any of them had the ability to remove or amend the defamatory material from the "publication." It remains to be seen whether wikis will be regarded as more akin to an internet service provider
Internet service provider
An Internet service provider is a company that provides access to the Internet. Access ISPs directly connect customers to the Internet using copper wires, wireless or fiber-optic connections. Hosting ISPs lease server space for smaller businesses and host other people servers...

, which is generally not held liable due to its lack of control over publications' contents, than a publisher.

It has been recommended that trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...

 owners monitor what information is presented about their trademarks on wikis, since courts may use such content as evidence pertaining to public perceptions. Jarvis notes, "Once misinformation is identified, the trade mark owner can simply edit the entry."

See also

  • Comparison of wiki software
    Comparison of wiki software
    The following tables compare general and technical information for a number of wiki software packages.-General information:-Target audience:-Features 1:-Features 2:-Installation:-See also:* List of wiki software* List of wikis* Wiki farm...

  • Content management system
    Content management system
    A content management system is a system providing a collection of procedures used to manage work flow in a collaborative environment. These procedures can be manual or computer-based...

  • Mass collaboration
    Mass collaboration
    Mass collaboration is a form of collective action that occurs when large numbers of people work independently on a single project, often modular in its nature...

  • Universal Edit Button
    Universal edit button
    The Universal Edit Button is a green pencil icon in the address bar of a web browser that indicates whether a web page is editable. It is similar to the orange "broadcast" RSS icon that indicates that there is a web feed available. Clicking the icon opens the edit window...

  • Wikis and education
    Wikis and education
    Wikis and education often go together. Many publicly-available wikis, such as Wikiversity, allow for self-education. Wikis are also sometimes used in classrooms for collaborative projects. Some teachers have found, however, that learners prefer to add their own content rather than rewrite others'...

External links

  • a wiki directory of wikis.
  • Exploring with Wiki An interview with Ward Cunningham
    Ward Cunningham
    Howard G. "Ward" Cunningham is an American computer programmer who developed the first wiki. A pioneer in both design patterns and Extreme Programming, he started programming the software WikiWikiWeb in 1994 and installed it on the website of his software consultancy, Cunningham & Cunningham , on...

    , by Bill Verners.
  • WikiMatrix website for comparing wiki software and hosts
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.