They use -bits- of the Zend framework, and from what they've said, not much of it.I have a feeling this will be implemented when xenForo implements Twitter integration etc. I may be over looking the design of xenForo here but since they are using the Zend Framework, couldn't they use Zend_Openid to make things easier?
Maybe if I said I worked for Twitter they would reconsider lol.
Google/Yahoo use a modified version I thought?openid would open the forum to google and yahoo users. i think both support openid based logins. and since people are already supposed to put in their email ids, connectivity with google and yahoo mails a lot of sense. not everyone is comfortable connecting their facebook profile to a forum.
here are some more: LiveJournal, MySpace, WordPress, Blogger, TypePad...