Well, I do not wanna say that I buy the concept of User Controlled Identities in it's "entirety" But however I'd like to say that I am trying pretty hard to buy into the "concept". Amartya Sen, The co-author of "Identity and Violence" says that the "freedom to choose one's identity affiliations is the antidote to divisive extremism"
Well. I'd not hesitate to do my part in playing a role to eliminate divisive extremism. And just to add to that I'm buying Kim's concept.. slowly.. very very very very slowly... 
However while on the "identity" subject, like the "rest of the world"... I too have a question for Kim. Whats with this symmetric proof key in the SAML assertion? Like me, I bet there are several-several folks out there who are awaiting an answer... Kim Please... Could you ? PLEASE...