haha carlos. you are missing the point here!
integration with facebook, twitter, openid, google accounts is not just about social networking.
it is about making it easy for new visitors to create an account as quickly as possible to start posting.
forum registration forms tend to be very complicated. these third party service makes it much faster as the user can just approve the connectivity, and you get access to their name/email address automatically.
the validation is also no longer required because these accounts are already validated.
when i landed here on this forum, i created my account within a matter of seconds using FB integration. i did not even have to pick a password.
i have personally found out that vb fb integration resulted in more new members joining the forum. because it is just easier to join it!