The problem with OpenID is branding – people get (very) confused when they get taken off site to login. I’ve watched usability testing of this, and it is truly horrible. Obviously this isn’t unique to OpenID – it applies equally to any federated identity solution (in fact – Shibboleth based federations are even worse than OpenID in this respect).

I think user education will help, but it would be really good to be able to extend OpenID to be able to put a logo on the identity provider’s site so the user can see they are logging into site “blah” via whatever open id provider.