(adsbygoogle = window.adsbygoogle || []).push({}); So anyways, for Premium NGU members, they have their own forum, not just their own section...

How exactly did they make this specialized separate forum in vBulletin?

What you do is set it up so it's not viewable from the index but still is accessible via the url. Then setup permissions for premiums to only get access to the forum then setup the forum link on like a toolbar like NGU.