A lot of people treat choosing their cofounder with even less importance than they put on hiring. Don't do this.

If you ever take your foot off the gas pedal, things will spiral out of control, snowball downwards.

I myself used to believe ideas didn't matter that much, but I'm very sure that's wrong now.

I really believe that the single hardest thing in business is building a company that does repeatable innovation... and just has this ongoing culture of excellence as it grows.

... but actually it sucks to have a lot of employees, and you should be proud of how few employees you have.

One of the pieces of advice that we give at YC is: try to work together on a project rather than just doing an interview.

If it works out, you're going to be working on this for 10 years.