Social Groups are an oft overlooked feature of vBulletin. You can access them by clicking on "Community" in the main nav bar or selecting "Social Groups" under Networking in the User CP... You can join an existing group or make your own group(s) if you're a premium member. Any groups you join or create will now show up like a subforum on the main forum page (where you go if you click on the JUOT logo) This should remind people they are there and help their popularity. You can restrict viewing of a social group to group members only and you can set it so only you can start new discussions(threads). It's like having your own little forum.