I made a long post about it when Bob first presented it at IIW and then the Burton Catalyst conference last June. Now anyone can get it here. See also Bob’s commentary on its evolution here.
Highly recommended for understanding the underlying dynamics of identity and relationship on the net.
Equals Drummond 
Yeah, after I first sign up for another free user account. I don’t need any more usernames and passwords. If the companies pushing federated identity don’t themselves lead by example, none of this stuff will ever amount to anything.
Well, it’s not quite true that anyone can get the paper, because they require you to disclose personal information before they’ll let you download the PDF, making it appear as if the Burton Group doesn’t know a damn thing about identity.