My friends are people who like building cool stuff. We always have this joke about people who want to just start companies without making something valuable. There's a lot of that in Silicon Valley.

People have really gotten comfortable not only sharing more information and different kinds, but more openly and with more people - and that social norm is just something that has evolved over time.

There are a few other things that I built when I was at Harvard that were kind of smaller versions of Facebook. One such program was this program called Match. People could enter the different courses that they were taking, and see what other courses would be correlated with the courses they are taking.

We have a pretty ambitious goal for the world. What we think will make the Web better. What we think will make all these businesses that integrate with us run more effectively. I think if we stay focused on doing that, that's really the main thing that we need to do.

Find that thing you are super passionate about.

Berlin definitely has one of the most vibrant of the startup scenes that I have seen. Not really just across Europe, but across the whole world in terms of cities. It's an interesting dynamic.

It is really important for us that people understand what the strategy is and that the real approach is to make everything social, not to build a vertical approach.