"Share of voice" revenue model: the solution for social networks?
wallen.typepad.com
wallen.typepad.com
Joe's Dance Club uses Twitter and Facebook to post news about shows. They want to promote these news feeds so that more customers will subscribe and hear about their cool shows. They pay Twitter and Facebook to "promote" their accounts in some way (maybe by ranking it higher in "things you might be interested in" suggestions, or featuring it on the homepage, or something).
I think it's hard to earn money this way without losing trust and compromising the product for your real users - just like paid placement in pre-Google web search.