Was reported many times from newbies that the thank button doesn't work.
I propose to add a script to enable the button after X messages in the forum (5? 10? 20?), and an alert box (or the top blue ribbon if is easier/better) to report this to the user.
As secondary minor thing I see that the names of who gives a thank on a post are visible in the russian side of the forum but not in the english side.