I mentioned this before. Only funny people like their own posts. This isn't really important until a respect extension is generated. Maybe if the money extension counted likes as money, but I believe it only gives credit to posts and replys.
I wish there was a dislike button. I believe the Like feature is to prevent people spamming threads with 'thank you' posts. It aught to be called thanks instead of likes, because the majority the people that reply also tend to like the post they reply to.
A dislike button would probly encourage OP to ask why user disliked it, but would also help noobs figure out what they did wrong ;( before people like freddy, reamed them with a 4 paragraph thrashing) without having it explained to them.