Disclaimer: I'm not a Microsoftie, just collecting some links and adding my own opinion. Microsoft use TFS heavily [1]. Right now I imagine most MS projects a

Disclaimer: I'm not a Microsoftie, just collecting some links and adding my own opinion. Microsoft use TFS heavily [1]. Right now I imagine most MS projects are TFS but it doesn't appear to be mandated. Maybe for the big, internal-only stuff. ASP.NET is hosted on CodePlex as a Git repo [2] and MEF is Hg [3]. They've just added Git support to TFS and that probably means a lot of MS projects will migrate to Git over time. [1] http://blogs.msdn.com/b/visualstudioalm/archive/2013/08/20/tfs-internal-usage-statistics-1st-half-cy-2013.aspx http://blogs.msdn.com/b/visualstudioalm/archive/2013/08/20/t... [2] http://aspnetwebstack.codeplex.com/ http://aspnetwebstack.codeplex.com/ [3] https://mef.codeplex.com/SourceControl/latest#.hgignore https://mef.codeplex.com/SourceControl/latest#.hgignore