i vote up comments yea, if they really do say something worth your while reading, either for a player or potentially for the game developer... oh, and i once voted up an incredible free rider track haha
I must admit i dont vote up comments. Partly because i dont really read comments but on the offchance i do read them, i usually just forget to vote. I shall start from now on though! (if people bribe me with cookies)
i've only done it once, to this dude who gave this really long comment on totem destroyer. actually part of it were the instructions to the game, which anyone can figure out without even reading the already appointed instructions in the description. i later went to this guy's profile and found that that was his only comment, and his only game rated. well im guessing on the game rating thing. i guess he expects a merit XD