A full-featured, web-based, multilingual, tightly integrated, all-in-one Wiki+CMS+Groupware, using PHP, ADOdb, Zend Framework, jQuery and Smarty. Can be used to create all sorts of Web applications
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, sites, portals, knowledge bases, intranets, and extranets.
Tiki offers a very large number of features "out-of-the-box", arguably more than any other Open Source Web Application. Highly configurable & modular, all the features are optional and administered via a web-based interface.
Major features include articles, forums, newsletters, blogs, a file/image gallery, a wiki, bug & issue tracker (form generator), a calendar, RSS feeds, a category system, tags, an advanced permission system and more.
About the "may conflict with GPL" note below: http://www.ohloh.net/forums/10/topics/1730 [Less]