In our profiles theres that area for Group Memberships - what's that for? How do we use it (or fill it rather)? No one ever belongs to a group from what I've seen, it just says "[username] is not a member of any public groups".
It is possible to create specific groups which users can join, either freely or once certain requirements are met. We don't have such a feature in place yet, because I do believe things would get really complicated, really fast.