It's a matter of invitations versus context. Twitter is really good at providing context, like, I''m having coffee at Third Rail Coffee.' Foursquare is about invitations to places. In this respect Foursquare has started to replace Yelp for me.

'Luck' is recognizing when the situation encourages build out and execution.

My mom cares that I tweeted a picture of my breakfast. She's knows I'm eating and I'm safe.

From a product standpoint, we want every touch point to feel magical. It inspires trust.

Meet customers where they are; question how to make the tools customers use more valuable.

The interesting products out on the Internet today are not building new technologies. They're combining technologies. Instagram, for instance: Photos plus geolocation plus filters. Foursquare: restaurant reviews plus check-ins plus geo.

I'm less interested in how people are following each other and more interested in how they are following topics and tweets themselves. People are following more key words and concepts and more ideas and acting on those rather than individuals or organizations.