No, if your thread is at the bottom of a page, and has not been answered, and you want to bring attention to it, you bump it, and it goes to the top of the list, and becomes bold, therefore bringing attention to it - doesnt quite work like that nate. You could type any word in the box, and reply, and it would go to the top, the word "bump" doesnt actually do anything, it's just a known forum word..
Actually it's when someone replies to the thread and it brings it up to the top. "Bumping" is just something that is known in the forums. People do it like when they have something they are selling and the thread has moved down to the second page or whatever, they "bump" it and bring it back to the top.