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

The entrepreneurs that really make it are the ones that start with an idea but are ready to change it at a moment's notice.

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.

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

Maintaining the trust of the consumer is critical to our business. We live and breathe only one thing, which is wanting to connect consumers with great local businesses, and I don't feel we can do that if we don't have effective ways to prevent gaming of the system.

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.