Bounty are the innovative strategist of many ico so that the members that will apply in ico are also promoting the tokens when doing posting and comments in some thread ..  Signature campaign is also a part of bounty program this bounty helps you to earn designated tokens/eth/btc (distribute of cryto currency/ that will promise to all the participant who are active ) some also payed after the ico,  You can determine it if its the profits is in "stake" .  The earnings are  depends on how active you are, how good is the word you used in posting and last but not the least it depends in your Rank .. The more higher the bigger profit.