Greenguy has been one of the first pioneers of porn marketing. He started back in 1990ies with free sites and hubs called link lists. The basic idea was to give away free samples of pay sites on mini portals called 'free sites' consisting out of index, main and gallery pages. Then those sites would be submitted to directories in exchange for reciprocal linking and traffic would flow like honey. This was before TGPs, MGPs, blogs and tubes were invented. Greenguy was one of the first market leaders and besides being an affiliate he also built a nice resource site with an active webmaster forum.