Login via OpenID

Now this allow user to login via multiple OpenID accounts, I'll implement the web part after this and see if it will confuse the Interface part or I can fix it later if I find using just one account is more suitable. Any idea ? :)
I have read some about the extension fields but I don't think/know what data we really need from user except user ID that we will use it to identify user in our system. My idea that moment was just a url from a user is enough and put whatever we got from the response as a user data into it. I will figure it out more the make data more useful :)