If identity providers are all in the business to make money, why should Facebook -- or any other private company -- be willing to act as an identity provider for federal sites?
It's been a long time coming. After any number of heavy-handed approaches to online identity management, the federal government looks like it is trying a more enlightened approach.
The challenge to professionals is twofold: create a positive identity and suppress a negative one. Information about you posted by others requires quick damage control.