I absolutely love StackOverflow\'s usage of OpenID for registration. How would I go about adding this to my site? It is PHP based. I went to openid.net and looked at the librari
OpenID is great, but have one big disadvantage. Let's imagine that I'm having Google account and Yahoo account. I will login using Google and then I will try to login using Yahoo. And it will be different accounts; it's really difficult to remember what openID provider I was using for registration... So, be careful with OpenID on entertainment websites, but it is still ok for developers websites.
Check OpenId class from Zend Framework.