GitVersionControl as a WebTwoPointOh social networking site. http://github.com . virtual colleagues read each others integration comments the way civilians read TwitterFeeds?.
Also increasingly used as a web hosting back end and document repository - http://pages.github.com/. Anyone (with access) can clone, edit and push their changes.
The SourceForge of Web 2.0.
See example of SmallestFederatedWiki.