Or not, if you listen to MS’ CIO Ron Markezich. In an interview with CNet, he gave this answer when asked about Linux usage at MS:

As a policy, I don’t run anything that competes with Microsoft. My goal is to make sure Microsoft products are the best products in the world. It’s an easy choice for me, in that sense–to run Microsoft technology. We don’t run Unix. We don’t run Linux. We don’t run Oracle. We’re 100 percent Windows, SQL Server. We do, in areas on the client, have an open-source client running–just for competitive analysis. As an IT organization, I have no skills and no ability and no purchasing of those products. We don’t even run J2EE. Everything is .Net.

Excellent strategy, Ron. Insularity: it’s what’s for dinner!

What a fucking tool.