I vote for creating a special button that not only indicates "thanks," but "totally awesome-agree with you--you da bomb" type sentiment.

Personally, I've found times where I like to thank someone for their post--thumbs up, whatever. But other times, there's really nothing you want to "say" except indicate that the post is the most awesome thing you've come across all day.

Okay, perhaps, a button like that could get overused. In that case, you make it so any user can only click on it say, 5 times, within a 24 hour period.

I don't know. Just a thought.