This CNet article about CodePlex has some VERY interesting points:
[...] Bayarsaikhan has posted the top 25 most active open-source projects on Microsoft's Codeplex site. Looking at the list, it looks like Microsoft developers spend their time doing much the same as the rest of the Java/other world: play games and make the Web world pretty with AJAX. You can see the top project interests below in the Codeplex tag cloud.
Codeplex is interesting to me for several reasons, but primarily because it demonstrates something that I've argued for many years now: open source on the Windows platform is a huge opportunity for Microsoft. It is something for the company to embrace, not despise.
And it does several things well (better than Sourceforge, in my opinion) [...]