The question I ask myself like almost every day is: 'Am I doing the most important thing I could be doing?' Unless I feel like I'm working on the most important problem that I can help with, then I'm not going to feel good about how I'm spending my time. And that's what this company is.

The most important thing is to keep your team as small as possible.

We've changed our internal motto from "Move fast and break things" to "Move fast with stable infrastructure."

At Facebook, we are squarely in the camp of the companies that work hard to charge you less ... I think it's important that we don't all get Stockholm syndrome and let the companies that work hard to charge you more convince you that they actually care more about you.

Focus relentlessly and passionately on the customer.

We've actually set the tech priorities driven off what we want to build for customers and what they're asking us to solve, and that's how it's going to be, and that is a cultural tension even today because we actually want some of both, we want ownership.