I'm not saying the whole world will work this way, but with Airbnb, people are sleeping in other people's homes and other people's beds. So there's a level of trust necessary to participate that's different from an eBay or Facebook.

What I've been surprised by is not how different people are, but how similar they are. There are certain types of Airbnb people, and they are in every city in the world - it's just that in some cultures, there is more of a generational divide.

In June 2010, I moved out of my apartment and I have been mostly homeless ever since, off and on. I just live in Airbnb apartments and I check in every week in different homes in San Francisco.

There are 500 million people on Facebook, but what are they saying to each other? Not much.

People in their forties, fifties, and onward enjoy the whole world of books in a different way than the Internet-age kids do.

It's very hard to do when you put trust on others capability more than yours.