If you have a native monetization system where the atomic unit of content is the ad unit, that scales down all the way to a small screen experience. That's why Twitter is performing so well on mobile.
Fred WilsonFoursquare's adoption of a game dynamic when it launched is a particularly clever implementation of a social hook.
Fred WilsonThe fact is that the amount of money startups raise in their seed and Series A rounds is inversely correlated with success
Fred Wilson