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.
Sometime doing the research the right way is an art.
Most of the time we don't know how to use the right tagline to find what we are looking for - however the forum are good way to find a good signature campaign. Whatsoever.