Actually, I'm not sure the Karma feature is still in use. I know there was talk of doing away with it at one time. If my memory serves:
Everybody starts out with 1 Karma block. As you post interesting or helpful articles, people could add to your Karma by clicking on the little Yin/Yang icon in the blue bar at the top of your post. You were also awarded a Karma block for reaching milestones in the number of posts you make. Obviously, the longer you have been around and the more posts you make, the more Karma you would receive. I guess there is a certain amount of "status" in having Karma but if the advice or information you get doesn't help, all the Karma in the world won't change that.
With or without Karma, it becomes clear very quickly who is here to help others and who isn't. If Karma still works it will come fast enough. The longer you are here and the more you help others, the more your reputation will grow. To me, that's worth a lot more than Karma.
"Time you enjoyed wasting is not wasted time"