I actually got a godo deal with social bookmarkings. Was pleased with the job. At any case I wouldnt go for likes and +1 as its difficult to find ones from a good geo location IP. No offense to anyone but a UK or US based aff sites (for example) will not benefit anything SEO wise from 500 likes from Indonesia.
I did like though the idea of affs exchanging likes. I’m up for it. PM me if you want.