I am experimentally turning on the Karma feature of the forum system. I may leave it on or I may turn it off if I don't like the results. So now you will notice a karma indicator next to each person's avatar, and you can "applaud" or "smite" a persons karma by clicking on links that may appear there. I think the rules for modifying karma are generally that you can't modify your own karma, and you may not be able to modify the karma of any thread in which you've posted, and if you post in a thread, all the karma you've changed in that thread will be undone (not sure about that yet). That's how it works on Slashdot.org anyway.
So what does this accomplish? Well I hope it doesn't inhibit any legitimate discussion. Even the posts in the Off-Topic forum are occasionally an interesting read. But this does mean that you might want to think twice before posting something that others will find meaningless or rude.