It is, but there's definitely not enough merit for my needs.  I was thinking about applying to be a merit source, but I don't know if I'd want to feel obligated to patrol for good posts.  There are ones I've run across since the whole system started that I'd like to have given merit to, but I ran out. 

Not a huge deal, but a "thanks" button could be used an infinite number of times, and it's not a bad suggestion at all--but I wouldn't sacrifice the merit system for it, because I do think there needs to be a quality-of-posts factor involved in the ranking up process, and merits provide that.