Open Source MediaWiki is the base for Wikipedia, and as such provides a familiar and popular basis for collaborative websites and crowd-sourced content. We currently have a number of Wikis running, only one of which is using the MediaWiki platform, because it has limited capability to restrict access to pages.
It takes a lot of complicated parts to put these worlds together, and ChaliceTech™ provides a repository for details on many of the components. (No trade secrets however). ChaliceTech Wiki is powered by MediaWiki.