Hubpages does rev sharing by showing their adsense code a certain % of the time and the authors code the remaining. Maybe this is a good way to monetize the free customers.
I'm not aware of a way to do it technically since I'd have to integrate with any sort of ad system they might be using. Most probably Adsense for feeds, which I don't think allows me to rev share. Also, for some reason adds in RSS feeds tend to convert terribly compared to normal adsense - at least from what I've seen.
