The first complaint we hear from everyone is: 'Why would I want to join this stupid useless thing and know what my brother's eating for lunch?' But that really misses the point because Twitter is fundamentally recipient-controlled - you choose to listen and you choose to leave. But you also choose what to put down and what to share.

The strongest thing you can cultivate as an entrepreneur is to not rely on luck but cultivating an ability to recognize fortunate situations when they are occurring.

Making something simple is very difficult.

Twitter has been my life's work in many senses. It started with a fascination with cities and how they work, and what's going on in them right now.

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.

What's interesting about Twitter and the influencers that someone follows - like, say, Shaquille O'Neal - is that they see someone who is using the exact same tools that they have access to, and I think that inspires this hope to be able to really engage with someone like him.

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.