Bounty hunters are essential in the core of the advertising projects. Without the bounty hunters, there is an insufficient amount of money that can be raised. Signature campaigns do really promote the ICO. Bitcointalk forum is the most effective way of advertising it.
According to the website analytics I saw, Bitcointalk signatures are among the worst ways of advertising an ICO. Every 10 sig campaign participants drove _at most_ 1 hit per day to the website. If you just copy/paste post material or have nothing of interest or value to say, nobody is going to click on your sig. I know people are under the belief that quantity matters over quality, but I have never seen that to be the case.