Imagine for a moment that, like most websites on the internet, The Markup had ads on our site. (We don’t.)
Which company gets to show you its ad?
When you loaded this page, you triggered a lightning speed auction for your attention.
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As this page loaded, it sent a signal saying there was an ad slot available, along with whatever information it knew about you.
An ad platform got the signal and started an auction for advertisers.
The advertisers analyzed your data to see if you were someone they wanted to reach.
Based on your information, one bidder matches you to a category called “Health & Fitness::Depression.” These categories group consumers together and are called audience segments.
This bidder, an ad agency working on behalf of a company, was interested in targeting you and placed the winning bid.
That winning bid decided which ad finally loaded on your page.
And yes, this all took place in an instant, mere milliseconds.
We found one ad platform had 650,000 different ways to label you based on sensitive information like visiting places of worship or an interest in addiction.
Read our investigation into Microsoft’s Xandr ad platform and browse through the lists of audience segments.