Internet users in the US and Europe have their data tracked and shared 178 trillion times every year as part of online advertising, a new report has found.

Real-Time Bidding (RTB) is a method by which advertisers can buy and sell impressions.

The process is simple – when you load a website, advertising space is auctioned off to the highest bidder, with the winner getting to display their ad. The process happens in the time it takes for the website to load.

However, the process is reliant on sharing user data. When the space is put up for auction, information about the user is shared with the advertiser to help them target their advert. For example, if a user has bought or shown interest in buying a new pair of shoes recently, that information could be shared with advertisers. This let them when someone is in the market for shoes and encourages shoes sellers to buy that impression.

However, this means the process records a user’s online activity, such as what they view online and their real-world location, regardless of how private or sensitive the data are.

The new report from the Irish Council for Civil Liberties (ICCL) explores the extent to which user data is used in RTB.

It found that, in Europe, RTB exposes people’s online activity and location data an average of 376 times a day. This increases for people in the US, who have their data exposed 747 times per day.

As such, of the 178tn times per year internet users across the US and Europe have their data shared, this breaks down to 107tn times for US users and 71tn for Europeans.

People in the UK have their data shared the most out of all European countries – 462 times per day.

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In addition, tech giant Google, the biggest company in RTB, allows 4,698 companies in the US and 1,058 in Europe to receive RTB data about people in the US. Microsoft provides data to 1,467 companies.

However, these companies are based around the world, including in Russia and China. The data is shared without any means of controlling what is then done with the advertising data.

For example, the report pointed to cases where RTB data was used to profile protestors connected with the Black Lives Matter (BLM) movement.

“Every day the RTB industry tracks what you are looking at, no matter how private or sensitive, and it records where you go. This is the biggest data breach ever recorded. And it is repeated every day,” said senior fellow at the ICCL Dr Johnny Ryan.

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