Does bitcointalk Forum rank really matter 's for signature bounty campaigns and what are the links between "Merits" and "bitcointalk forum rank" ?
Higher rank = Higher rewardsI would advise you to read this sticky
https://bitcointalk.org/index.php?topic=2766177.0 to really understands what is Merit system. But for twitter and facebook campaign, I don't think the rank matter though, its purely based on your followers and friends as far as I know. And go explore the Meta section as well, so if you have questions then search around and I'm sure that you will find helpful threads in there.