Information on individual Irish internet uses, from their locations to what they are reading online, are being exposed to advertisers and data companies an average of 392 times a day, according to figures compiled by the Irish Council of Civil Liberties (ICCL).
ICCL estimates that so-called retail-time bidding (RTB), the online ad-targeting industry that profiles internet users' intimate characteristics, broadcasts information to third-party companies about 178 trillion times a year in the US and Europe alone. It has long held that the system amounts "to the largest data breach ever".
"Europeans and US internet users' private data is sent to firms across the globe, including to Russia and China, without any means of controlling what is then done with the data," the ICCL said in a new report, adding that the RTB industry generated an estimated $117 billion (€112.4 billion) in the US and Europe last year.
In Europe, RTB exposes individuals’ data at an average of 376 times a day, according to the report.
ICCL senior fellow Dr Johnny Ryan is currently in the middle of a High Court challenge against the Data Protection Commission's alleged failure to fully investigate a complaint made about the possession by Google and members of the IAB Europe, the digital advertising industry body, of personal data.
In his complaint, Dr Ryan raised concerns including that the RTB systems used by the two firms involve unauthorised and potentially unlimited disclosure and processing of personal data.
His complaint contains several instances where he claims that Google and IAB have breached EU general data protection regulation (GDPR). The legal case, launched in March, is up for mention in the High Court on Monday.
Google and Microsoft are the world's biggest RTB companies, according to ICCL. Other large, less-well-known players include Index Exchange, PubMatic and Magnite. ICCL's data does not include figures from Amazon and Facebook.