Blogs | Information democracy | Online tracking industry / AdTech | Profiling practices

Real Time Bidding: The auction for your attention

By EDRi · July 4, 2019

The digitalisation of marketing has introduced novel industry practices and business models. Some of these new systems have developed into crucial threats to people’s freedoms. A particularly alarming one is Real Time Bidding (RTB).

When you visit a website, you often encounter content published by the website’s owner/author, and external ads. Since a certain type of content attracts a certain audience, the website owner can sell some space on their website to advertisers that want to reach those readers.

In the earlier years of the web, ads used to be contextual, and the website would sell its ad space to a certain advertiser in the field. For example, ads on a website about cars would typically relate to cars. Later, ads have become more personalised, and they now focus on the unique website reader. They have become “programmatic advertising”. The website still sells its space, but now it sells it to advertisement platforms, “ad exchanges”. Ad exchanges are digital marketplaces that connect publishers (like websites) to advertisers by auctioning the attention you give that website. This automated auction process is called Real Time Bidding (RTB).

How does Real Time Bidding work?

Imagine auctions, stock exchange, traders, big screens, noise, graphs, percentages. Similarly, RTB systems facilitate the auction of website ad space to the highest bidding advertiser. How does it work?

A website rents its advertising space to one (or many) ad exchanges. In the blink of an eye, the ad exchange creates a “bid request” that can include¬† information from the website: what you’re reading, watching or listening to on the website you are on, the categories into which that content goes, your unique pseudonymous ID, your profile’s ID from the ad buyer’s system, your location, device type (smartphone or laptop), operating system, browser, IP address, and so on.

From their side, advertisers inform the ad exchange about who they want to reach. Sometimes they provide detailed customer segments. These categories have been obtained by combining the advertisers’ data about (potential) customers, and the personal profiles generated by data brokers such as Cambridge Analytica, Experian, Acxiom or Oracle. The ad exchange has now a complex profile of you, made of information from the website supplying the ad space, and information from the advertiser demanding the ad space. When there is a match between a bid request and the advertiser’s desired customer segment, a Demand Side Platform (DSP) acting on behalf of thousands of advertisers starts placing bids for the website’s ad space. The highest bid wins, places its ad in front of a particular website viewer, and the rest is history.

Click to watch the animation


Every time you visit a website that uses RTB, your personal data is publicly broadcasted to possibly thousands of companies ready to target their ads. Whenever this happens, you have no control over who has access to your personal data. Whenever this happens, you have no way of objecting to being traded. Whenever this happens, you cannot oppose to being targeted as Jew hater, incest or abuse victim, impotent, or right wing extremist. Whenever this happens, you have no idea whether you are being discriminated.

Whenever this happens, you have no idea where your data flows.

EDRi’s members suing against RTB

Real time bidding poses immense risks for our human rights in the digital space, specifically for the rights recognised in the EU General Data Protection Regulation (GDPR). More, it puts you at high risks of being discriminated. For these reasons, several EDRi members and observers have taken action and filed lawsuits against RTB in different EU countries. Privacy International, Panoptykon Foundation, Open Rights Group, Bits of Freedom, Digitale Gesellschaft, digitalcourage, La Quadrature du Net and Coalizione Italiana per le Libertà e i Diritti civili are taking part in a wider campaign that urges the ad tech industry to #StopSpyingOnUs.

Support their effort in fighting for your rights and spread the word!

Read More:

Privacy International full timeline of complaints

GDPR Today: Ad Tech GDPR complaint is extended to four more European regulators

Prevent the Online Ad Industry from Misusing Your Data – Join the #StopSpyingOnUs Campaign

The Adtech Crisis and Disinformation – Dr Johnny Ryan

Blogpost series: Your privacy, security and freedom online are in danger (14.09.2016)