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.

I think Twitter is best when it sparks conversations elsewhere. To use YouTube and Facebook and all the tools we have available to us today to respond and also promote and answer and engage is awesome.

My goal is to simplify complexity. I just want to build stuff that really simplifies our base human interaction.

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 fell in love with flora of all types, especially ferns. Loved the sparse structure and repetition of shape - almost fractal.

An idea that can change the course of the company can come from anywhere.

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.