Two user groups, one public and one restricted

[tenres]

I want to have two user groups in my forums: one public that anyone can join, and one restricted to users who are given access by the admin.

I would like to understand the ways that vbulletin would handle this kind of thing. By what criteria are possible to grant access to the restricted group.

I know for example that people can pay to upgrade to a different set of forums. I'm looking for this kind of thing, but using something other than payment as a way to give them access. I just don't know what is possible.

[feldon23]

vBulletin has Primary Usergroups, of which each user has 1, and Additional Usergroups, of which users can be a member of as many as you want.

You can manually move users from one usergroup (Registered) to another usergroup (say, Subscriber).
You can manually add users to different groups which grant additional access (Photography, Developer, Beta Tester, etc.).
You can set up a Subscription which users must pay and then they are promoted into your Subscriber usergroup.

And vBulletin has promotions where a user can be automatically bumped into another group based on length of time they have been a member, number of posts, and reputation (Likes).

vBulletin Usergroups are additive. Meaning you don't have to try to get all your usergroups perfect so they overlap properly. If I am a member of Registered, Subscriber, and a special group called Beta Testers, then I would inherit the most beneficial permissions from all 3 groups.

There are also free plugins at vBulletin.org which further extend the functionality of Usergroups.

Out of the box, only Administrators can change a user's groups. There are some modifications at vBulletin.org to grant some of this functionality to Moderators.

[tenres]

Thank you for this thorough clarification. That tells me what I need to know.

My users are going to purchase a product (an 8 week self help program) and then they will be given access to the forums which are relevant to the content of the program. I think I will be able to make it work with the paid registration.