I have this massive notebook called IDEAS and another one called PERSONAL IDEAS and another one called CRAZY IDEAS.

I think the hallmark of a really good entrepreneur is that you're not really going to build one specific company. The goal - at least the way I think about entrepreneurship - is you realize one day that you can't really work for anyone else. You have to start your own thing. It almost doesn't matter what that thing is.

The single most important top-level trend is the shift to mobile.

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

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

We're all put on Earth for a limited amount of time. Am I using in a way that is great, or good enough, or wasteful?

If I see what you're up to on Facebook but I don't see your updates on Flickr, I'll still care about Facebook.