I find this method little hard to find campaigns. I scrolled through 3 pages of yahoo's posts and i see not any signatures campaigns or bounty campaigns to join. the thing is these people are also users of this forum not just managers. they do normal posts too.
I think best way is to just go to Services and join open campaigns . for bounties there is a section for bounties too. to join a good bounty just check which bounty token is listed in exchanges then join it.