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.

In early 2008, it was confirmed that there would be an opportunity to build applications for the iPhone. We were fortunate enough to make the right call on that: to bet early, to put resources into it and have a pretty good application in the store at the moment when it opened.

About every year or two, there is a moment of truth where there's some new development in the marketplace, some new technology, some sort of existential crisis. You just have to be vigilant about looking out for those moments.

Choose something you are passionate about - or a pain point that has affected you and that you feel really needs to be changed.

Everyone is panicked about the transition to mobile. I don't lose any sleep whatsoever.

Starting a company, your success is going to be very dependent on how you adapt. You're going to make decisions, you're going to make bets; most of them are going to turn out to be wrong.

Maintaining the trust of the consumer is critical to our business