Look to the top of the page. See that banner ad? Believe it or not, that hasn’t just been randomly squirted out to you. It is a calculation made by one of the most complex computational systems on the planet, the global ad network exchange, which crunches a surprising volume of data about you in real time and auctions your eyeballs off to the highest bidder in little under a fraction of a second.

A great interactive put together by CMSummit and sponsored by Adobe, Behind the Banner traces what happens between the moment you request a webpage and the moment an ad is displayed to you. It’s actually surprisingly complex.





When you first load a webpage, the first thing that happens is it generates an impression, which is then forwarded to an ad server. So far, so good, but you might be surprised by how much that ad server knows about you.

Using information gathered from Internet cookies, social media, and more, an ad server is capable of generating a unique profile of various metrics, almost like a QR code, that contains everything it knows about you: how old you are, your relationship status, what websites you browse, where you’re located, etc.

With that code generated, the ad server tries to match it against a pre-sold inventory of ads, almost like a key fitting into a lock. If the key fits, the process ends there, and an ad is returned that advertisers believe jibes with your unique personal profile. But it’s what happens if the server doesn’t have an ad that matches where things gets interesting.





Without a pre-sold ad to serve you, an ad server forwards your profile to an international ad exchange, where a network of different ad servers examine it and bid on it in real time. In a fraction of a second, a host of third-party servers around the world go into a bidding war for the opportunity to show you an ad, with the highest bidder taking the prize and filling your eyes.

All of this happens in literally the blink of an eye. On any given webpage, this same extraordinary computation engine might process thousands of different profiles every second, matching up what it knows about you, the reader, against the millions of different products and services that hawkers around the world want to sell you.