When Yelp first took off, our rankings on Google would fluctuate wildly.

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

On mobile, what are the core apps? It's basically messaging, mapping and review data.

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.

I think with every successful consumer Internet business, there will be lawyers that are interested in going after your company, especially when they think that there's a financial incentive.

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.

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