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

I think Twitter is the future of communications and Square will be the payment network.

I was fascinated with jeans, because you can impress your life upon the jeans you wear. The way you sit imprints on the jeans.

Your job as an executive is to edit, not write. It's OK to write once in a while but if you do it often there's a fundamental problem with the team. Every time you do something ask if you're writing or editing and get in the mode of editing.

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.

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