You don't have to start from scratch to do something interesting. You don't have to start from scratch to have a massive impact on the world. You have to have a good idea. You have to convince other people of those good ideas. And you have to push as quickly as possible.

As CEO, my main job is editor-in-chief.

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.

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.

It's empowering to be asked to look at what's possible, not told how to do it.

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.

Starting anything is a roller coaster with the highest highs and lowest lows.