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.

There is this cat and mouse game that plays out over time where our team comes up with new and interesting ideas to identify content that we shouldn't recommend, and over time people are constantly probing that, trying to figure out how can they get around that and get a better reputation on Yelp.

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.

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.

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

The biggest thing is to create a product that consumers find useful. As more and more people like something, it becomes harder and harder to have a conspiracy theory about it.