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.

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

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.

A lot of what Groupon is generating is demand for something people didn't know they wanted.

Theres simply anger over the accountability that Yelp brings and also this feeling of powerlessness because so much power is now being put in the hands of the consumer. But the important thing that gets lost with some of these business owners who are very upset with us is its the whole picture that counts.

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.

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.