Funny you ask this because I just asked this question to some of my co-workers the other day. You have to have certain permissions to mark answers correct, so there are only a few people of HUB who can do so.
So, though kinda funny, your post answered my question though I don't believe it is correct. Since I posted this, I can mark your answer as "Helpful" or "Correct". So I guess it is the originator. Perhaps there is something permission wise as well?