It's supposed to be just like life: you don't pick up after your damn' dog, I get dogma all over my shoes, I'm gonna bust you one so you don't do that again. No, wait, you wanted karma.
Okay, karma can be good (green) or bad (red). If someone does something nice for you on the boards, you click on "karma" and send them a little green dot.
Now, if you go around ASKING for karma for nothing, you're gonna get red. Green is for people who put up something worth reading, not for whiners and bums.
Keep it in perspective. "Why do you care about dots so much? Are you like, Pac Man or something?"