[Mark.A]

Is it possible to have new users automatically added to custom usergroups once they activate their account?

My forum is going to be split into two distinct subject areas and I want all new members to have access to all areas once they register but be able to opt out of either subject area if they so choose.

The best way I thought of doing that would be to create two custom usergroups each with access to their own subject area forums and have new members added to both usergroups on joining. Then they can just leave the group of either subject area if they want to and will no longer see that areas forums. However, I haven't found a way of adding new users to the two custom usergroups. Is there a way? or is there another way of going about this?