Sourcegraph - Sourcegraph is a free, self-hosted code search and intelligence server that helps developers find, review, understand, and debug code. Use it with any Git code host for teams from 1 to 10,000+.
Community Questions for Confluence - Keep questions and answers in one place with an engaging, community-driven Q&A discussion forum, powered by Confluence
Atlassian Fisheye - With FishEye you can search code, visualize and report on activity and find for commits, files, revisions, or teammates across SVN, Git, Mercurial, CVS and Perforce.
Stack Overflow for Teams - Everything you love about Stack Overflow in a private space.
Krugle - Krugle is the complete enterprise solution for search targeted to the development organization.
Question2Answer - A Q&A site helps an online community to share knowledge.