Much of the data shared and matched in cross-tracking across devices is "untraceable by observers", according to a report by the Federal Trade Commission. The FTC said that it was "concerned about how this information could be used for marketing purposes." Although the study could not say for certain that collected data was used to correlate user behaviour, it said its findings demonstrate "a broad range of companies possess the capacity" to do so across devices.
Much of the data shared and matched in cross-tracking across devices is "untraceable by observers", according to a report by the Federal Trade Commission. The study ran multiple tests on two devices that monitored 100 websites and found that companies dealing in probabilistic cross-device linking collected data from 34% of the sites visited, while 106 third-party domains shared browser-specific cookie identifiers with 210 third-party companies. Although the study could not say for certain that collected data was used to correlate user behaviour, it said its findings demonstrate "a broad range of companies possess the capacity" to do so across devices.