open source blog, wiki

[BLOG, Forum]
TatterTools - TextCube (TNC, DEV)
ZeroBoard - XpressEngine

phpBB,
Simple Machines Forum (SMF)
atlassian confluence (enterprise wiki)


[Version Control, BugsTracking, WIKI]
TRAC, GForge, nForge
cvs, svn, git

[WIKI]
MediaWiki - WikiMediaFoundation(pidia, book, dic, quote)
MoniWiki (source), MoinMoinWiki,


[CSM] - Content Management System
OpenSource CSM

drupal

[Groupware]
eGroupware