Certainly anything that is news or opinion needs to be free on the Web, because the Web is this very fluid medium that is very much driven by links and the flow of visitors through a discussion via links.

My venture investing career has three phases, all roughly 6-8 years long. The first, at Euclid, was software to Internet. The second, at Flatiron, was Internet to bubble. And the third, at USV, has been web 2 to mobile. I have always used a new firm to denote a new investment phase for me. Throw away the old. Start with the new.

Foursquare's adoption of a game dynamic when it launched is a particularly clever implementation of a social hook.

I believe the mobile OS market will play out very similarly to Windows and Macintosh, with Android in the role of Windows. And so if you want to be in front of the largest number of users, you need to be on Android.

The fact is that the amount of money startups raise in their seed and Series A rounds is inversely correlated with success

If you want to create something great and do it faster than the competition, you need to be action oriented.

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.