Via David Pennock who has much more info. – MicroSoft’s short letter to the CFTC. – PDF file
MicroSoft simply says that it supports the lobbying of CIM (Yahoo! + Google) in favor of (enteprise and public) prediction markets —PDF file. So, you would ask, why doesn’t MicroSoft join CIM? I heard the rumor that MicroSoft doesn’t like CIM’s legal counsel (Paul Architzel). Maybe Paul Architzel was opposite to MicroSoft, in a prior suit. Take this as a rumor, not as a fact —beware the “class-action” defamation suit. 
