on a recent visit, the homepage for one popular U.S.-based news site sent 20 requests to 10 ad exchanges, each of which likely offered the space to hundreds of advertisers. It also set 47 cookies with unique tracking IDs, many of which log user data such as location, gender, age, and likes and dislikes based on browsing behavior. These data give advertisers a sense of how valuable you might be as a customer, and therefore how much to bid to show you an ad. When one of the advertisers wins the auction, an ad appears on your screen. The whole process takes less than a tenth of a second.
As a side business, every company involved in any step of the process may also try to place a cookie or tracker to collect more data on you for later use. Such companies often swap data to try to identify users they have in common, and they may pull in your email address, name, public records, and credit card history.
« Older "where it’s O.K. to be closed-minded" | Hi there! This is, um, Skynet. Newer »