Adblock
Encyclopedia
Adblock Plus is a content-filtering
Content filtering
Content filtering is the technique whereby content is blocked or allowed based on analysis of its content, rather than its source or other criteria. It is most widely used on the internet to filter email and web access.- Content filtering of email :...

 extension for Mozilla Firefox
Mozilla Firefox
Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers...

 (including Firefox for mobile) and Google Chrome
Google Chrome
Google Chrome is a web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows on September 2, 2008, and the public stable release was on December 11, 2008. The name is derived from the graphical user interface frame, or...

 web browsers. ABP, a fork
Fork (software development)
In software engineering, a project fork happens when developers take a legal copy of source code from one software package and start independent development on it, creating a distinct piece of software...

ed version of Adblock, allows users to prevent page elements, such as advertisements
Online advertising
Online advertising is a form of promotion that uses the Internet and World Wide Web to deliver marketing messages to attract customers. Examples of online advertising include contextual ads on search engine results pages, banner ads, blogs, Rich Media Ads, Social network advertising, interstitial...

, from being downloaded and displayed.

How it works

Like Mozilla's built-in image blocker, Adblock blocks HTTP
Hypertext Transfer Protocol
The Hypertext Transfer Protocol is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web....

 requests according to their source address and can block iframes, script
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....

s, and Flash
Adobe Flash
Adobe Flash is a multimedia platform used to add animation, video, and interactivity to web pages. Flash is frequently used for advertisements, games and flash animations for broadcast...

. It also uses automatically generated user stylesheets to hide elements such as text ads on a page as they load instead of blocking them, known as element hiding.

History

Michael McDonald created Adblock Plus 0.5 that improved on Adblock by incorporating the following features:
  • Whitelisting
  • Support for blocking background images.
  • Subscription to filters with a fixed address and automatically update them.
  • The ability to hide HTML elements allowing a much greater range of images to be blocked.
  • The ability to hide ads on a per site basis instead of globally.
  • Memory leak
    Memory leak
    A memory leak, in computer science , occurs when a computer program consumes memory but is unable to release it back to the operating system. In object-oriented programming, a memory leak happens when an object is stored in memory but cannot be accessed by the running code...

     fixes


McDonald discontinued development and transferred the name to Wladimir Palant, who released Adblock Plus 0.6 with a rewritten codebase in January 2006. PC World
PC World (magazine)
PC World is a global computer magazine published monthly by IDG. It offers advice on various aspects of PCs and related items, the Internet, and other personal-technology products and services...

chose Adblock Plus as one of the 100 best products of 2007.

Adblock Plus for Google Chrome is available since Dec 2010. The code for Adblock Plus for Google Chrome is largely based on the now renamed "AdThwart". The former developer of AdThwart is a contributor to the project.

Filters

Basic filter rules can include wildcards represented by asterisks (*). Sites and objects can be whitelisted with filters that start with two at signs (@@). Regular expression
Regular expression
In computing, a regular expression provides a concise and flexible means for "matching" strings of text, such as particular characters, words, or patterns of characters. Abbreviations for "regular expression" include "regex" and "regexp"...

s delimited by slashes (/) can be used. Adblock Plus also supports a more-sophisticated syntax that gives fine-grain control over filters.
An example of the sophisticated filtering would be 'wikipedia.org#div(id=siteNotice)', which will hide the siteNotice element used by Wikipedia
Wikipedia
Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 20 million articles have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site,...

 to display donation requests.

Filter subscriptions

Users can add external filtersets. Adblock Plus includes the ability to use one or more external filter subscriptions that are automatically updated. Filterset.G
Filterset.G
Filterset.G was a third-party set of filters for the Adblock extensions used in the Mozilla Firefox web browser. The filterset contained pre-made and regularly updated filters that removed ads from various ad providers...

 is incompatible with this system (and Adblock Plus specifically recommends against using Filterset.G for other reasons as well), but other filtersets can be added by typing their addresses. A list of known Adblock Plus subscriptions is maintained on the Adblock Plus official website.

EasyList

EasyList is the most popular Adblock Plus filter list with over 12 million subscribers. Created by Rick Petnel, it became officially recommended by the Adblock Plus program, and filter lists for other languages were built on top of it. Petnel died in 2009 and Palant named a user going by the name "Ares2" as the new maintainer.

Fanboy Lists

http://fanboy.co.nz/
Fanboy's list is the second most popular Adblock Plus filter list. Fanboy started the service in early 2009. The lists available are Adblock List (Main list), Tracking List, and Annoyance Block List. The list are available for Firefox, Iron-Chrome, IE and Opera.

Both EasyList and Fanboy's have had controversy over whitelisting tracking and advertising sites.

ABP features improvements to the user interface, filter subscriptions, and an element hiding extension. It has since become the most popular extension for Firefox, with around 12 million daily users.

Although Adblock Plus is not supported by Internet Explorer, it is possible to export a filter list such as EasyList or Fanboy's List to an XML document which can then be imported into Internet Explorer's InPrivate content filtering.

Controversy

A number of website operators, who use online advertisements to fund the hosting of their websites, argue that the use of ad-blocking software such as Adblock risks cutting off their revenue stream. While some websites have successfully implemented subscription and membership based systems for revenue, the majority of websites today rely on online advertising to function. The assumption that users can visit a website for free, with advertisements to pay for the hosting, has led some operators to go as far as to call the use of Adblock tantamount to theft.

Some websites have taken counter-measures against ad-blocking software, such as attempting to detect the presence of ad blockers and informing users of their views, or outright preventing users from accessing the content unless they disable the ad-blocking software. There have been several arguments supporting and opposing the assertion that blocking ads is wrong. Adblock Plus developer Wladimir Palant responded to this in his blog.

Detection

Some webmasters have used JavaScript to detect the effects of the popular Adblock filters. This has been done by generating a honeypot
Honeypot (computing)
In computer terminology, a honeypot is a trap set to detect, deflect, or in some manner counteract attempts at unauthorized use of information systems...

-like URL and verifying its delivery and also by more advanced verification of the DOM
Document Object Model
The Document Object Model is a cross-platform and language-independent convention for representing and interacting with objects in HTML, XHTML and XML documents. Aspects of the DOM may be addressed and manipulated within the syntax of the programming language in use...

 after the web page is rendered in the web browser to ensure the expected advertising elements are present.

These methods do not detect the presence of the Adblock extension directly, only the effects of the filters, and are vulnerable to continued updates to the filters, and by whitelist-filtering web scripts with an extension such as NoScript
NoScript
NoScript is a free and open-source extension for Mozilla Firefox, SeaMonkey, and other Mozilla-based web browsers, created and actively maintained by Giorgio Maone, an Italian software developer and member of the Mozilla Security Group...

.

An attempt was made to detect the plug-in itself but that detection method was rendered unusable by the 0.7.5.2 update of Adblock Plus.

See also

  • Flashblock
    Flashblock
    Flashblock is a content-filtering extension for the Mozilla Firefox- and Mozilla Application Suite-based web browsers. Flashblock allows users to prevent page elements, such as HTML object tag Browser plug-ins and advertisements, from being displayed...

  • Ad filtering
    Ad filtering
    Ad filtering or ad blocking is removing or altering advertising content in a webpage. Advertising can exist in a variety of forms including pictures, animations, text, or pop-up windows. More advanced filters allow fine-grained control of advertisements through features such as blacklists,...

  • Online advertising
    Online advertising
    Online advertising is a form of promotion that uses the Internet and World Wide Web to deliver marketing messages to attract customers. Examples of online advertising include contextual ads on search engine results pages, banner ads, blogs, Rich Media Ads, Social network advertising, interstitial...

  • List of Firefox extensions
  • Hosts file
  • IE7Pro
    IE7Pro
    IE7Pro is an add-on for Internet Explorer 6, 7, 8, and 9 that aims to enhance the feature set provided by the browser. IE7Pro adds features such as tab enhancement, an ad blocker and flash blocker, mouse gestures, inline search, privacy enhancements, online bookmark service, Greasemonkey-like user...

     (an equivalent on Microsoft Internet Explorer including other features)

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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