I'll explain to you people the best I can.

If you look beside the post number on a certain thread, there is a little justice scale icon and the little green dot, is your Karma count. If you approve/disapprove of someones post, you click that justice scale, and a little box will come up where you clicked. Yopu can write a comment if you wish, or nothing at all. It then gets added to that persons Karma bar (the green dots).

As for viewing who voted for you for either good or negative response, I'm not sure on that yet, but I hope this explain how it kind of works.

They had the same deal at Overgrow, exact same thing, and no, you can't vote for yourself.