Technology has come a long way since PayPal.

Facebook and Myspace are the U.S. audience, which is tried and true when it comes to being susceptible to ads.

If you're building a social product, you're still living in the last century if your product doesn't work on Facebook.

We're becoming slaves to our social networks - and that's not a bad thing. You like your favorite networks, so do you friends, and pretty soon you have market winners.

Mobile is the perfect example of what is enabling economic growth in the technology sector.

You're going to pull out your phone and try to use whatever is the most appropriate app on your iPhone or your Android device. Yelp saw that very early on. And when we launched the mobile product, we saw immediate growth, and we were stunned.

I've been developing mobile for years before anybody else really thought it was that important.