Just a few thoughts (off the top of my head):
Minimum requirements should include a minimum length of SW membership... say like a week (or more), maybe be limited to verified members or VIP members or maybe some usage level and not have more than one account.
Group owner/creator should be required to clearly outline rules and purpose of any group being created and have the ability to decline membership to their group. Should be able to appoint associate moderators (maybe up to 2) and they (owner and moderators) should have the ability to remove group members who break rules or go off on tangents.
Groups promoting hatred of any kind/variety, violence, extreme fetishes, pedophelia of any type, etc., should not be allowed and all groups should be monitored to some degree by SW admin to preclude these type of groups.