Mobile is absolutely the platform that everybody is looking at. So look for GPS combined with applications like Foursquare. In a few years, I'll be walking down a street looking into shops, and the deals will find my phone rather than me look for them. As I'm there in front of the Gap, the phone will say: "Here are the jeans you love, or that your friends love, and here's a deal if you buy now." Retailers will use all these converging technologies.

Some analysts think we're looking at a second tech bubble. Are they wrong?

I see some things that are promising and some things that are troubling.

The promising thing is that companies like Groupon, Facebook, and Zynga are already making money, whereas early dot-coms were just a promise to make money. Still we really need to be careful that these companies aren't fads. That's why engagement is so important. Facebook and Groupon are good at holding on to their huge audiences.

What's not promising is we're coming out of a recession, and people are looking for the next big thing. There is lots of money -- both smart and dumb -- on the sidelines.

What sector are you nervous about? Where is the dumb money going?

I'm skeptical about standalone products. Money is going to three big sectors. Money is going to geolocation, money is going to [online] games, and money is going into the group coupon world. As a standalone, these sectors are risky. But if these capabilities converge, [e.g. a group coupon technology that uses geolocation to offer deals] they'll be more sustainable.

Last question. Every industry has a competitor. Groupon has Living Social. Foursquare has Gowalla. What's Facebook's competition?

Facebook is really proving to be an enigma. The way I see it, pretty soon you're not going to go to the Best Buy website. You'll go to Facebook, where you can talk to friends, use geo-location, play games, and get coupons. A website will be a brochure for an organization.

Facebook is looking to be the place for the entire world to transact. That is a big big vision. I think that's what we're seeing. They want to be PayPal, eBay, Amazon, Foursquare, Groupon, all in one place.