Tiki Wiki CMS Groupware - Tiki Wiki CMS Groupware, also known as Tiki (or TikiWiki), is a full-featured, web-based, multilingual, all-in-one Free/Libre Open Source Software solution. Tiki can be used to create all kinds of web apps, portals, knowledge bases, intranets, etc.
JoinDiaspora - JoinDiaspora is a privacy-aware, distributed, open source social network which are open to anyone.
Pmwiki - PmWiki is a wiki-based system for collaborative creation and maintenance of websites.
Apache JSPWiki - Apache JSPWiki is an open source Wiki engine, feature-rich and built around standard JEE components.
WikkaWiki - WikkaWiki is a flexible, standards-compliant and lightweight wiki engine written in PHP.
PBworks Wiki Hub - PBworks Wiki Hub provides tools to build wikis for your organization.