You don't have to start from scratch to do something interesting. You don't have to start from scratch to have a massive impact on the world. You have to have a good idea. You have to convince other people of those good ideas. And you have to push as quickly as possible.

Pick a movement, pick a revolution and join it.

IM is interesting because you look at your buddy list and, at a glance, see what your friends are listening to, what they're working on, what they're doing. The problem was that you were bound to the computer keyboard.

Meet customers where they are; question how to make the tools customers use more valuable.

The interesting products out on the Internet today are not building new technologies. They're combining technologies. Instagram, for instance: Photos plus geolocation plus filters. Foursquare: restaurant reviews plus check-ins plus geo.

Build what you want to see in the world.

I loved couriers. You had this transfer of physical information happening throughout the city and the world. Someone picking up the package, putting it in a bag, going somewhere, taking it out of the bag, giving it to someone else. I thought that was so cool. I wanted to map it, to see that flow on a big screen.