This joint announcement by Microsoft and RSA was not entirely unexpected. The dance partners are the interesting part. But, being modestly aware of Microsoft's business position in general, I would say that this is not necessarily an endorsement of a solution as much as it is the earliest alternative out of the gate for Microsoft.
Regardless, it'll probably do good things for RSA, for Microsoft, and for the digital identity space -- inasmuch as it's a concrete step forward, by someone, that can be accepted, rejected, upgraded, or replaced. It's motion anyways.