OK, so the previous versions of .NET Passport have been pretty nasty to work with and get working (and keep working!) - this as well as user disaffectation have led to several high-profile clients
dropping the use of the .NET passport sign-on mechanism.
I've just been having a look at Passport V3.0 (for a Microsoft owned site) - and it's very cool, the technology has taken a HUGE leap forward - I can't discuss specifics (NDA etc...). God, I wish they'd done this 2 years ago (when I first saw documents relating to this change) - they could really have moved things forward!