Company and community sharing/not sharing revenue

Revenue sharing, from ads or similar income generators, between companies and their connected communties providing the content is uncommon, and not an expected relation between community and a given company, should money at some point be generated.
(E.g MySpace or YouTube)
A company host the site, design the frames of the site.
Users have their playground, designing the activity and the information flow.
Sharing of revenue is only common when a contract between user and company explicitly state that, typically a cornerstone in attracting a community
But more often it is the case that companies have direct affiliate programs, stating the benefit of one user, to connect others. (E.g Rebtel Affiliate program on Facebook).