Lots of good stuff there, but a key one is slide 8. In the question session Richard confirmed that Source Depot (the custom version of Perforce) was at that time still used for the source management although TFS was used for bug tracking etc for Office and Windows.
Don't know what has happened in the intervening years...
I believe that they do use TFS on a lot of the internal projects though and that Visual Studio is now done in TFS.