I work (part time) with the Dept of Interior. The reason for the Microsoft-centric requirements is due to all of the lawsuits against DoI. As far as I know, electronic "discovery" tools used by lawyers and law firms aren't compatible with Google's cloud, but are compatible with Microsoft's (and Lotus Notes - shudder). Perhaps there will be a few products handling Googles product in a year or 2.

The lawsuits against Interior have to do with Indian tribes being cheated out of royalties going back, oh, a hundred years or more. One book where this subject was touched upon (and gives an idea of the size of the discrepancies) is Sinister Pig. http://www.amazon.com/Sinister-Pig-Tony-Hillerman/dp/0060194... Pretty much any tribe with oil, gas, coal, uranium or any other economically valuable mineral is involved in sueing Interior. This means that just about every tribe is sueing Interior.

Employee orientation with Interior includes some explanation of these suits as well as what needs to be preserved.