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.

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.

There's an entire universe in every single tweet, and it all really depends on the content as far as how it's going to spread.

Build what you want to see in the world.

A number of people in the United States, almost everyone, is using plastic cards to pay for things, but it's extremely difficult to accept these cards. So let's make it's easy and take more and more of the friction out as we can.

TweetDeck is a very interesting client, because it presents a view that no other client in the world presents, which is this multicolumn, massive amounts of information in one pane. And people really, really enjoy that.

Don't avoid eye contact and don't be late