A reputation system much like the one at vBulletin would be great. Short explanation: The reputation you give is based on the reputation you have. Example: I have 100 rep points, if I rep a member, he get 10 rep points. I have 10 rep points, if I rep a member, he get 1 rep points. That really encourages users to help others, so they get a good reputation. I know much forums that only survives because of this reputation system.