This is a pretty good feature. I like it. It makes it so you can agree with a poster's thoughts without cluttering up the thread with "me too" responses.
But as of right now, it's a bit cluttered. Why don't we just include the thanks in the post itself, rather than make it look like a new post. An example from my home forum:
http://www.wordforge.net/showthread.php?t=68598
(Except those say "XPoster agrees" instead of "Thanks")