Ok, Lets say for example, you are a really nice helpfull member, Admin/Guides may put a little dot of green on your karma bar. And if you are a unhelp-full spamming member, you will get a little bit of yellow karma. Red, Orange, Yellow=Not good. Green=Good.
Most member's have no karma, that doesnt mean they are un help-full, it just means they haven't made thay karma winning post yet h34r:
If you read the rules you would know. I cant post a link, My computer is cranky this morning.