If you're building a social product, you're still living in the last century if your product doesn't work on Facebook.

Having a highly homogeneous background, education, values, preferences, etc, in the very early team is better than not - cuts down on time-wasting arguments.

The very first company I started failed with a great bang. The second one failed a little bit less, but still failed. The third one, you know, proper failed, but it was kind of okay. I recovered quickly. Number four almost didn't fail. It still didn't really feel great, but it did okay. Number five was PayPal.

You're going to pull out your phone and try to use whatever is the most appropriate app on your iPhone or your Android device. Yelp saw that very early on. And when we launched the mobile product, we saw immediate growth, and we were stunned.

I've been developing mobile for years before anybody else really thought it was that important.

PayPal once rejected a candidate who aced all the engineering tests because for fun, the guy said that he liked to play hoops. That single sentence lost him the job.

Ignore your mistakes. The number one thing to worry about is -Am I doing what I'm good at?