Like that. Once you reach a certain amount of posts, 500 I think, you are granted the power to give and take Karma from other members. It's really nothing more than a way to reward or punish someone for posts they have posted in the past and things they have done. For instance, if someone makes a very good point in a discussion thread, I might give them a point of Karma for it. On the other hand, if someone gets torqued off that Ruski is making "Gabriel's Mother" jokes again, I might take a point away.
When this system first started, we had two columns, one for positive karma and one for negative karma. It was possible to have say 25 points of negative karma and 10 points of positive karma, thus giving you an overall score of -15 karma. Now it is just the one column which can still be negative. Ingo Monk (our sysop) can post the actual historical karma log for your profile (say +35, -82) but only does it upon request.
For quite a while I was the Negative Karma King. But, alas, no more. I did, however, have the destinction of being the MOST karmic person on the board for a bit. It's nice to know you can make an impact.

Gabriel