Take care of yourself: When you don't sleep, eat crap, don't exercise, and are living off adrenaline for too long, your performance suffers. Your decisions suffer. Your company suffers. Love those close to you: Failure of your company is not failure in life. Failure in your relationship is.

Hard things are valuable; easy things are not so valuable. Reaching the mountaintop is rewarding because it is hard. If it was easy, everybody would do it.

Our problem wasn’t that it blew up and was impossible to scale, but there were some bad choices made. One of the biggest lessons time after time was to focus. Do fewer things.

Every major communication tool on the Internet has spam and abuse problems. All email services, blogging services and social networks have to dedicate a significant amount of resources and time to fighting abuse and protecting their users.

Assume the best but hire paranoid people.

Failure of your company is not failure in life. Failure in your relationships is.

User experience is everything. It always has been, but it's undervalued and underinvested in. If you don't know user-centered design, study it. Hire people who know it. Obsess over it. Live and breathe it. Get your whole company on board.