"Consumer Reports found that a total of 186,892 companies sent data about them to [Facebook]. 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."
In other words, there's a whole industry that makes a ton of revenue on providing information to Facebook. It's likely that each of these providers has many other downstream customers. The result is an extensive privately-run surveillance network. #Technology