Real Time Bidding

Digital Privacy

Every time you visit a ad-enabled website, your personal information is sent to potentially hundreds of advertisers in a process known as real-time-bidding.


The industry is controlled almost entirely by Google.

Information potentially included

The information provided to each bidder by Google is specified by the Authorized Buyers real-time bidding protocol, specified at

Google Customer Match

To make this more concrete: suppose a company wants to acquire data about expecting mothers. It can buy a list of a million device IDs that a data broker believes to belong to such women. The company can upload this list to Google and target an ad at those IDs. If even a small fraction—say, 1%—click on the ad, then 10,000 people are sent to the advertiser’s landing page, where they automatically share their IP address, cookies, and possibly geolocation data. The company now has sensitive medical data about 10,000 people served up to it on a silver platter. (Google prohibits targeting based on medical and other characteristics in its Customer Match terms of service, but it is unclear how the company audits or enforces them.) —

Referenced By

Privacy Is Power