Reputation
It really has two purposes: helping members figure out who to listen to, and helping mods figure out if certain members are causing trouble.
Once your own reputation is at 20 (everyone starts at 10), you can start giving and taking points to/from others. So, if you really like someone's posts, or you respect his/her advice, etc., you can add points to that person's reputation. That helps newbies realize that this is someone to trust.
On the other hand, if you think a member is giving out bad advice, is being cruel or snotty or dishonest, etc., you can "disapprove," thus taking away reputation points.
Mods have double the power when it comes to giving and taking points, and for every 100 days or 1000 posts a member is here, he/she gets more power, too.
The mods will take those reputation points into consideration if they're considering warning or banning anyone, and I'll take them into consideration if I'm considering "promoting" anyone.
I may also give extra priviledges to members with good reputation scores as time goes on. Have to see how well we all use this feature.