Use OpenID. I never give my user information to another site, if possible. OpenID is the most portable of those implementations. Edit: Ah, didn't see at first

Use OpenID. I never give my user information to another site, if possible. OpenID is the most portable of those implementations. Edit: Ah, didn't see at first that you can only have one form of login. I guess you can use FBConnect (and that provides a significant user base), but I won't be signing up...