[Colin F]

This allows you to combine that.

Say you have three forums, a public one, and two private ones (A + B)

registered users have access to the public forum

now you want users to be able to subscribe, to either A, B or both.
when they subscribe, they'll automatically be added to the specific usergroup.

In the vB2 Version, you'd need 4 usergroups:

- registered
- registered + A
- registered + B
- registered + A + B

now think how many usergroups you save if you have a much more complicated setup...