Consumer Reports: “By now most internet users know their online activity is constantly tracked. No one should be shocked to see ads for items they previously searched for, or to be asked if their data can be shared with an unknown number of “partners.” But what is the scale of this surveillance? Judging from data collected by Facebook and newly described in a unique study by Consumer Reports (PDF), it’s massive, and examining the data may leave you with more questions than answers. Using a panel of 709 volunteers who shared archives of their Facebook data, Consumer Reports found that a total of 186,892 companies sent data about them to the social network. On average, each participant in the study had their data sent to Facebook by 2,230 companies. That number varied significantly, with some panelists’ data listing over 7,000 companies providing their data. The Markup helped Consumer Reports recruit participants for the study. Participants downloaded an archive of the previous three years of their data from their Facebook settings, then provided it to Consumer Reports. By collecting data this way, the study was able to examine a form of tracking that is normally hidden: so-called server-to-server tracking, in which personal data goes from a company’s servers to Meta’s servers. Another form of tracking, in which Meta tracking pixels are placed on company websites, is visible to users’ browsers…”