A Karma feature would help to self-police this site.

One example of how to implement this is :

"Any member can receive karma at any point while they are a member here once they've made their first post. However, to grant karma to others, you must have a Posts: count of at least 50 in these forums. Once you have made those 50 posts, you will see a new button in the same section of each members posts (right below their Karma: count line) that looks like this:

[applaud]

If you press that button on a person's post, their Karma count will increase by one. Some people call this giving a person a karma cookie.

There is a limit on granting karma. You may only award a person a single applaud within a one hour period.

Finally, the spirit of karma is to show appreciation for a post that a person has made. If you feel that a certain post is above average or especially helpful, then hit that applaud link under the member's id for that post and award them a cookie."

The text above was lifted from Wilders Security Forum

It sounds more complicated than it really is. It just gives you the ability to show your appreciation of other Posters (no relation).

Of course negative Karma would also be good.