MediaWiki

MediaWiki is a open source wiki software written in PHP, originally for use on Wikipedia. It is now used by several other projects of the non-profit Wikimedia Foundation and by many other wikis. Very iftne use by IT departments to implement quickly a wiki, Mediawiki lacks many of the features an enterprise needs for a enterprise wide wiki. Look at Xwiki, TWiki ou Mindtouch Core for alternative,enterprise grade, wiki software.