Proprietary

• 37signals
  37signals
  37signals is a privately held web application company based in Chicago, Illinois. The firm was co-founded in 1999 by Jason Fried, Carlos Segura, and Ernest Kim as a web design company. Segura left in 2000 and Kim left in 2003, leaving Fried as the only remaining founder.Since mid-2004, the...
  
   Backpack
• Alfresco
  Alfresco (software)
  Alfresco is a Free/Libre enterprise content management system for Microsoft Windows and Unix-like operating systems. Alfresco comes in two flavours. Alfresco Community Edition is free software, LGPL licensed open source and open standards. Alfresco Enterprise Edition is commercially & proprietary...
  
   - a collaboration portal that allows export of site calendars in the iCalendar format.
• Atlassian
  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 :...
  
   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...
  
  
• Apple
  Apple Computer
  Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
  
   iCal
  ICal
  iCal is a personal calendar application made by Apple Inc. that runs on the Mac OS X operating system. iCal was the first calendar application for Mac OS X to offer support for multiple calendars and the ability to publish/subscribe calendars to WebDAV server....
  
  
• Bookeo - a booking system with calendar integrated with iCalendar.
• Calendarscope A calendar program that exports icalendar (.ics) files
• Contactizer
  Contactizer
  Contactizer Pro is a contact manager, task manager, event manager, communication manager and project manager developed exclusively for Mac OS X, in Cocoa....
  
  
• Buni Meldware Communication Suite
• EventForward - an iOS application that allows export of calendar events in the iCalendar format.
• Facebook
  Facebook
  Facebook is a social networking service and website launched in February 2004, operated and privately owned by Facebook, Inc. , Facebook has more than 800 million active users. Users must register before using the site, after which they may create a personal profile, add other users as...
  
  
• FirstClass
  FirstClass
  FirstClass is a client/server groupware, email, online conferencing, voice/fax services, and bulletin-board system for Windows, Macintosh, and Linux...
  
  
• Google Calendar
  Google Calendar
  Google Calendar is a free time-management web application offered by Google. It became available on April 13, 2006, and exited the beta stage in July 2009...
  
  
• Huddle
  Huddle (software)
  Huddle is a web-based team collaboration and project management application developed in the UK.Huddle is privately held and funded by Eden Ventures and Matrix Partners.-Features:...
  
  
• ICS Importer https://market.android.com/details?id=jitdesign.icsimport Android Icalendar file import to the Android Calendar
• Jalios JCMS
• KeepandShare - online suite of web applications, including a web calendar that allows import and export of calendar events in the iCalendar format.
• KeepMeBooked - web-based guesthouse/B&B software
• LifeSize Bridge
• LiquidPlanner
  LiquidPlanner
  LiquidPlanner, Inc. is a project management software company based in Washington. The firm was founded in 2006 and launched their first release to a public beta in 2008....
  
  
• Lotus Notes
  Lotus Notes
  Lotus Notes is the client of a collaborative platform originally created by Lotus Development Corp. in 1989. In 1995 Lotus was acquired by IBM and became known as the Lotus Development division of IBM and is now part of the IBM Software Group...
  
  
• Meeting Maker (PeopleCube)
  Meeting Maker
  Meeting Maker is a cross-platform personal calendar and group scheduling software application from PeopleCube. The product dates back to 1990, when it was originally Mac-only software created by Callisto Corporation and published by ON Technology. It was released for Microsoft Windows as Meeting...
  
  
• melssCRM (CRM)http://www.melsscrm.com/http://blog.melsscrm.com/2011/02/manage-activities-on-google-calendar-apple-ical-microsoft-outlook-and-more/
• Microsoft Entourage
  Microsoft Entourage
  Microsoft Entourage was an e-mail client and personal information manager developed by Microsoft for Mac OS 8.5 and higher. Microsoft first released Entourage in October 2000 as part of the Microsoft Office 2001 office suite; Office 98, the previous version of Microsoft Office for Mac OS included...
  
  
• Microsoft Exchange Server
  Microsoft Exchange Server
  Microsoft Exchange Server is the server side of a client–server, collaborative application product developed by Microsoft. It is part of the Microsoft Servers line of server products and is used by enterprises using Microsoft infrastructure products...
  
  
• Microsoft Office Outlook 2000
  Microsoft Outlook
  Microsoft Outlook is a personal information manager from Microsoft, available both as a separate application as well as a part of the Microsoft Office suite...
  
  
• Microsoft Office Outlook 2007
  Microsoft Outlook
  Microsoft Outlook is a personal information manager from Microsoft, available both as a separate application as well as a part of the Microsoft Office suite...
  
  
• Microsoft Office Outlook 2010
  Microsoft Outlook
  Microsoft Outlook is a personal information manager from Microsoft, available both as a separate application as well as a part of the Microsoft Office suite...
  
  
• Microsoft Works
  Microsoft Works
  Microsoft Works is an integrated package software that is produced by Microsoft. Works is smaller, less expensive, and has fewer features than Microsoft Office or other major office suites. Its core functionality includes a word processor, a spreadsheet and a database management system...
  
   Calendar
• myBookingWizard http://www.mybookingwizard.com/ Web 2.0 online booking application
• MyPhoneExplorer
  MyPhoneExplorer
  MyPhoneExplorer is a proprietary freeware desktop application allowing management of Sony Ericsson and Android mobile phones. It is developed in Austria but has been translated into many languages, including English. It is available from multiple download sites and has been downloaded over 1.5...
  
   http://www.fjsoft.at/ FreeWare phone manager for SonyEricsson mobile phones.
• Novell Groupwise
  Novell GroupWise
  GroupWise is a messaging and collaborative software platform from Novell that supports email, calendaring, personal information management, instant messaging, and document management. The platform consists of the client software, which is available for Windows, Mac OS X, and Linux, and the server...
  
  
• Nokia N9
  Nokia N9
  The Nokia N9 is a smartphone made by Nokia based on the MeeGo "Harmattan" mobile operating system, the first from Nokia on the MeeGo OS...
  
   Calendar
• Nokia N900
  Nokia N900
  The Nokia N900 is a smartphone made by Nokia. It supersedes the Nokia N810. Its default operating system, Maemo 5, is a Linux-based OS originally developed for the Nokia 770 Internet Tablet. It is the first Nokia device based upon the Texas Instruments OMAP3 microprocessor with the ARM Cortex-A8...
  
   Calendar
• Nuvvo
  Nuvvo
  Nuvvo was an on-demand e-learning service designed for individual instructors which has since been shut down by its parent company Savvica, Inc. in anticipation of its new iteration of learning environment, LearnHub. It costs nothing to use, though it has some ads and gets a percentage if you...
  
  
• Projektron BCS
• Rainlendar
  Rainlendar
  Rainlendar is a calendar program for Windows, Mac OS X and Linux. Prior to version 2, it was licensed under the GNU GPL as free software.Rainlendar is characterized by very small space and memory requirements, stability, and an easily customizable user-interface . The calendar can be transparently...
  
  
• Sun Java Calendar Server
  Sun Java Calendar Server
  The Sun Java System Calendar Server is Sun's calendar server. The currently available version is 6.3 which is now part of the Sun Java Communications Suite....
  
  
• Teamwork agenda and meetings synchronizer
  Teamwork (software)
  Teamwork is a web-based wide scoped project and groupware management tool developed by Open Lab, an Italian software house founded in 2001. It won the 17th Jolt Productivity Award in 2007 in the project management category....
  
  
• Westlaw
  Westlaw
  Westlaw is one of the primary online legal research services for lawyers and legal professionals in the United States and is a part of West. In addition, it provides proprietary database services...
  
   (TWEN)
• WinCalendar http://www.WinCalendar.com/ Converts ICAL to Word and Excel formats (Windows).
• Windows Calendar
  Windows Calendar
  Windows Calendar is a calendar application that is included with Windows Vista and Windows Server 2008. It natively supports the iCalendar file format, and has the ability to publish and subscribe to web-based calendars by using HTTP and WebDAV...
  
  
• Windows Live Calendar
  Windows Live Calendar
  Windows Live Hotmail Calendar is a time-management web application by Microsoft as part of its Windows Live services. It is integrated into Windows Live Hotmail, the way that MSN Calendar was integrated into the MSN Hotmail service...
  
  
• Wrike
  Wrike
  Wrike is an online tool and application service provider for project management and collaboration developed by Wrike Inc. The company was founded in 2006 and launched its first release to a public beta in 2007.- History :...
  
  
• WebTrain
  WebTrain
  WebTrain Communications provides web conferencing services for educational training, business meetings, presentation webinars and live auctions. WebTrain is a privately held Canadian company established in 1999.-History:...
  
   - Web Conferencing
  Web conferencing
  Web conferencing refers to a service that allows conferencing events to be shared with remote locations. Most vendors also provide either a recorded copy of an event, or a means for a subscriber to record an event. The service allows information to be shared simultaneously, across geographically...
  
   Meeting Reminders
• Yahoo Calendar
• Yandex
  Yandex
  Yandex is a Russian IT company which operates the largest search engine in Russia and develops a number of Internet-based services and products. Yandex is ranked as 5-th world largest search engine...
  
   Calendar
• Zimbra
  Zimbra
  Zimbra Collaboration Suite is a groupware product created by Zimbra, Inc., located in Palo Alto, California, USA. The company was purchased by Yahoo! in September 2007, and subsequently purchased by VMware on Tuesday, January 12, 2010. The software consists of both client and server components...
  
   Collaboration Suite

Open source

• Calcurse Text based calendar and to do organizer.
• Chandler
  Chandler (PIM)
  Chandler is a personal information management software suite described by its developers as a "Note-to-Self Organizer" designed for personal and small-group task management and calendaring. It is free software, previously released under the GNU General Public License, and now released under the...
  
  
• Citadel
  Citadel/UX
  Citadel/UX is a collaboration suite that is descended from the Citadel family of programs which became popular in the 1980s and 1990s as a bulletin board system platform. It is designed to run on open source operating systems such as Linux or BSD...
  
  
• CiviCRM
  CiviCRM
  CiviCRM is a web-based, internationalized suite of computer software for constituency relationship management, that falls under the broad rubric of customer relationship management...
  
   With its CiviEvent module
• Claws Mail
  Claws Mail
  Claws Mail is a free, GTK+-based, open source email and news client. It offers easy configuration and an abundance of features. It stores mail in the MH mailbox format and also the Mbox mailbox format via a plugin...
  
   (the vCalendar plugin is required to handle iCalendar in Claws Mail)
• Darwin Calendar Server
  Darwin Calendar Server
  The Darwin Calendar Server is a standards-compliant server that allows multiple users to collaboratively share calendaring information. It provides a shared location on the network to store schedules, and allows users to manage and send invitations. It was publicly released during Apple's Worldwide...
  
  
• DAViCal
  DAViCal
  DAViCal is a server for calendar sharing. It is an implementation of the CalDAV protocol which is designed for storing calendaring resources on a remote shared server...
  
   server for calendar sharing
• Dolibarr
  Dolibarr
  Dolibarr ERP/CRM is an open source/free software package for small and medium companies, foundations or freelancers. It includes different features for Enterprise Resource Planning and Customer Relationship Management but also other features for different activities.- Features :There are several...
  
   ERP & CRM
• Drupal
  Drupal
  Drupal is a free and open-source content management system and content management framework written in PHP and distributed under the GNU General Public License. It is used as a back-end system for at least 1.5% of all websites worldwide ranging from personal blogs to corporate, political, and...
  
   with its event module
• etm
  ETM
  ETM may stand for:*Enhanced Thematic Mapper Plus, an instrument on board the Landsat 7*Eric the Midget*European Travel Monitor, the original name of the World Travel Monitor*The car number plate code for Tomaszów Mazowiecki, Poland...
  
   (text based event and task manager) export to iCal
• Evolution the Gnome email/calendar client
• Hippo CMS
  Hippo CMS
  Hippo CMS is an open-source information centered Content Management System. The Hippo CMS project was initiated and is maintained by . It's targeted at medium to large organisations managing content for multi-channel distribution like web sites and intranets...
  
  
• Horde
  Horde (software)
  Horde is a PHP-based Web application framework.It offers applications such as the Horde IMP email client, a groupware package , a wiki and a time and task tracking software.-Horde Email Platform:...
  
  
• Joomla there are several plugins available
• Kontact
  Kontact
  KMail supports folders, filtering, viewing HTML mail, and international character sets. It can handle IMAP, IMAP IDLE, dIMAP, POP3, and local mailboxes for incoming mail. It can send mail via SMTP or sendmail...
  
   (namely KOrganizer and KMail)
• Lightning
  Lightning (software)
  The Lightning project, announced on December 22, 2004, and in development by the Mozilla Foundation, produces an extension that adds calendar and scheduling functionality to the Mozilla Thunderbird mail and newsgroup client and SeaMonkey internet suite...
  
   (Mozilla extension for Thunderbird
  Mozilla Thunderbird
  Mozilla Thunderbird is a free, open source, cross-platform e-mail and news client developed by the Mozilla Foundation. The project strategy is modeled after Mozilla Firefox, a project aimed at creating a web browser...
  
   mail/news client and SeaMonkey
  SeaMonkey
  SeaMonkey is a free and open source cross-platform Internet suite. It is the continuation of the former Mozilla Application Suite, based on the same source code...
  
   internet application suite)
• Mozilla Thunderbird
  Mozilla Thunderbird
  Mozilla Thunderbird is a free, open source, cross-platform e-mail and news client developed by the Mozilla Foundation. The project strategy is modeled after Mozilla Firefox, a project aimed at creating a web browser...
  
   mail/news client (with Lightning
  Lightning (software)
  The Lightning project, announced on December 22, 2004, and in development by the Mozilla Foundation, produces an extension that adds calendar and scheduling functionality to the Mozilla Thunderbird mail and newsgroup client and SeaMonkey internet suite...
  
   extension)
• Moodle
  Moodle
  Moodle is a free source e-learning software platform, also known as a Course Management System, Learning Management System, or Virtual Learning Environment...
  
   will export iCalendar data or let you subscribe to a Moodle iCalendar feed.
• Mulberry
• Org-mode
  Org-mode
  Org-mode is an editing mode in the text editor Emacs which supports the editing of plain text hierarchical documents. It has specific support for a number of different use cases, such as writing to-do lists, project planning, and writing web pages...
  
   - an Emacs mode for organising your life.
• OLAT
  OLAT
  OLAT is an acronym for Online Learning And Training. It is a web application – a so called Learning Management System that supports any kind of online learning, teaching, and tutoring with few educational restrictions. OLAT is free software and is open source. Its development started in 1999 at the...
  
   - LMS supporting import and export of personal and shared calendars via iCalendar
• Opengroupware.org
  OpenGroupware.org
  SOGo is an Open Source collaborative software server with a focus on simplicity and scalability...
  
  
• Open-Xchange
  Open-Xchange
  Open-Xchange Server is an open source project sponsored by Open-Xchange, Inc., developing collaboration software; i.e. email, calendaring, address book, etc. Product offerings based on Open-Xchange Server are marketed under the brand of Open-Xchange Server and various other names, e.g. 1&1...
  
  
• Osmo (PIM)http://clayo.org/osmo/
• phlyMail (groupware)
• PHP iCalendar - viewer/parser to display iCals in a Web browser
• Plone open source content management system
• Request Tracker
  Request Tracker
  Request Tracker, commonly abbreviated to RT, is a ticket-tracking system written in Perl used to coordinate tasks and manage requests among a community of users. RT's first release in 1996 was written by Jesse Vincent, who later formed Best Practical Solutions LLC to distribute, develop, and...
  
   - a ticket-tracking and call-center application. Exports iCalendar data.
• SeaMonkey
  SeaMonkey
  SeaMonkey is a free and open source cross-platform Internet suite. It is the continuation of the former Mozilla Application Suite, based on the same source code...
  
   internet application suite (with Lightning
  Lightning (software)
  The Lightning project, announced on December 22, 2004, and in development by the Mozilla Foundation, produces an extension that adds calendar and scheduling functionality to the Mozilla Thunderbird mail and newsgroup client and SeaMonkey internet suite...
  
   extension)
• 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...
  
   semantic extension to MediaWiki
  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...
  
  
• Simple Groupware
  Simple Groupware
  Simple Groupware is a groupware package written in PHP. It uses the MySQL database . It contains a calendar system, an email client, an inventory system, and a number of other features. Simple Groupware is Free Software released under the GNU/GPL License.The software contains about 30,000 lines of...
  
  
• SOGo
  Sogo
  Sogo Co., Ltd. is a department store chain that operates an extensive network of branches in Japan. It once owned stores in locations as diverse as Beijing in China, Causeway Bay in Hong Kong, Taipei in Taiwan, Jakarta, Medan, Bandung & Surabaya in Indonesia, Kuala Lumpur in Malaysia, Singapore,...
  
   - a integrated groupware with Apple iCal, Mozilla Thunderbird support and native Outlook compatibility
• SPIP
  SPIP
  SPIP is a free software content management system designed for Web site publishing, oriented towards online collaborative editing....
  
   a CMS that allows the export of its site calendar in the iCalendar format.
• Tiki Wiki CMS Groupware Calendar exports to iCal and generates hcal
• Tryton
  Tryton
  Tryton is a three-tier high-level general purpose computer application platform on top of which is built a business solution through a set of so-called Tryton modules....
  
  
• Sunbird
  Mozilla Sunbird
  Mozilla Sunbird is a free and open source, cross-platform calendar application that was developed by the Mozilla Foundation, Sun Microsystems and many volunteers...
  
   (a Mozilla stand-alone application)
• TYPO3
  TYPO3
  TYPO3 is a free and open source web content management framework. It is released under the GNU General Public License. It can run on several web servers, such as Apache or IIS, on top of many operating systems, among them Linux, Microsoft Windows, FreeBSD, Mac OS X and OS/2.-History:TYPO3 was...
  
   via its Calendar Base Extension
• vTigerCRM (CRM)http://www.vtiger.com/
• WebGUI
  WebGUI
  WebGUI is an open source content management system written in Perl and released under the GNU General Public License.The system permits non-technically minded users to arrange content in pages and layouts, containing 'Assets' which permit website visitors to view and interact with various types of...
  
  
• Webical
  Webical
  Webical is a web application to view and edit multiple iCalendars. Its features include progressive enhancement, a plugin framework that can be used to enhance the GUI and to add additional back end providers, pluggable authentication, and internationalization. Dutch and English localizations are...
  
  
• Web2project
  Web2project
  web2project is a web-based, multi-user, multi-language Project Management application. It is an open-source software and free for any uses and is maintained by an open community of volunteer programmers.-Structures and Features:...
  
  
• Wordpress
  WordPress
  WordPress is a free and open source blogging tool and publishing platform powered by PHP and MySQL. It is often customized into a content management system . It has many features including a plug-in architecture and a template system. WordPress is used by over 14.7% of Alexa Internet's "top 1...
  
   via plugins
• YaMA - Yet another Meeting Assistant
• Zimbra Collaboration Suite
  Zimbra
  Zimbra Collaboration Suite is a groupware product created by Zimbra, Inc., located in Palo Alto, California, USA. The company was purchased by Yahoo! in September 2007, and subsequently purchased by VMware on Tuesday, January 12, 2010. The software consists of both client and server components...
  
  
• Zotonic
  Zotonic
  Zotonic is an Open Source CMS and Web Framework built in Erlang and released under the Apache 2.0 license. The CMS part of Zotonic is designed to be user friendly and hides development tasks from the user. One of Zotonic's primary goals is speed, and it claims to be up to ten times faster than PHP...
  
  via mod_calendar