“If you start putting ads into Twitter’s search results, there is no reason you could put ads wherever. I have ads in my Gmail and I accept it because the service is free.
Alternatively, if Twitter started to treat my Twitter stream as a combination of blog and RSS feed, why can’t I put my own ads there? I have ads on my blog; so why not just institutionalize the ads, and share the revenue with the Twitterers?”
fwiw I think Stowe is on to something here, where one looks at the app/service/platform whatever and then really closely at where the value is and then add new/unusual ways of implementing business models that are consistent with the new value, new relationships, new context that is being created, not old regimes or paradigms.