At Twitter, mobile is in our DNA ... For us, it's all about mobile, and it always has been.

The reason I really started running was for meditative purposes. I would pick some problem to have in my head while running.

Embrace your constraints.

You have to think for an email. What's the subject? What's it about? It takes two seconds to think about that. So you have to think, Is this a work thing or a social thing? Which? Then you get into a situation that you don't want to be in, because then people are thinking about it too much.

You can shut down a service, and yet people will find ways to communicate.

We hired a CSR person at Twitter, years before we hired our first sales person, to make sure we had a culture and impact of doing good.

If you make the opportunity. you'll be the first in the position to take advantage of it.