i rarely do it, but if somethings worthy of it. Then i will
and also, i dont do it just based on how long a comment is, and i find that stupid. The person could just be rambling on about nothing in their comment, and then ur giving them a merit. You should actually read the thing and then determine if it gets a merit or not...
I vote up lots of comments, but that's kinda because I go through lots of comment pages... And I have upvoted one comment on a profile, it was when Zoph won a contest and etc etc.