All the users are surfing around all over the place. We're looking at finding users. There's a profile on Jane, from what we know from your cookies and your web surfing. We know enough about you that you may fit into a campaign we're doing for a hospital in Philadelphia, or a political campaign, or a car. If you fit in as a user whom we want to target, then where are you? On your iPad, or the New York Times, or the Inquirer. Let's serve her an ad. We want to target people like Jane and Jane look-alikes. Other people also want to sell to Jane. Suddenly, there's competitive bidding. It's like Google, the whole search world. You bid to get your listing at the top. The same thing for the banner ads we're serving. Once we profile who we want, our traders put all the parameters in. Then, literally, we press a button and start delivering ads.