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.

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.

Technology has come a long way since PayPal.

You can't get married to any one particular plan. That is the biggest lesson I learned at PayPal.

You can have successful teams where people hate but deeply respect each other; the opposite (love but not respect among team members) is a recipe for disaster.

Right now, nearly all the apps on Facebook take a week to build. No more.

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.