In the very beginning, Yelp started as a service where we really didn't think people would write reviews for fun. The whole concept of user-generated content was pretty nascent in 2004.

One of the challenges of buying local advertising is, how do you know if it worked? How do you know if it's got value? We're moving toward an e-commerce experience for local, an Amazon-like experience for local.

Consumers are empowered by Yelp and tools like it: before, when they had a bad experience, they didn't have much recourse. They could fume, but often nothing else other than tell their friends.

When you read reviews on Yelp, you get a good sense of what's going to happen when you walk in the door of that business. The challenge is that there are fifteen million businesses in the U.S., and its very hard to communicate with all of them about how Yelp works, and why it works the way it does.

The 3D-printing technology has been developing at a very rapid pace.

I'm a technology person, but I'm not a science person.

With today's technology, you can actually see the baby grow, move, and hear their little heart beats.

I really don't spend any time on the Internet, so I guess I live a little under a rock in that respect.