What do these privacy violations have in common? They share a source of data that’s shockingly pervasive and unregulated: the technology powering nearly every ad you see online.

Each time you see a targeted ad, your personal information is exposed to thousands of advertisers and data brokers through a process called “real-time bidding” (RTB). This process does more than deliver ads—it fuels government surveillance, poses national security risks, and gives data brokers easy access to your online activity. RTB might be the most privacy-invasive surveillance system that you’ve never heard of.