Speaking of carriers, some have been known to inject IDs into their users' requests, so that site owners can later buy those profiles from them: https://arstech

Speaking of carriers, some have been known to inject IDs into their users' requests, so that site owners can later buy those profiles from them: https://arstechnica.com/information-technology/2014/10/verizon-wireless-injects-identifiers-link-its-users-to-web-requests/ https://arstechnica.com/information-technology/2014/10/veriz... That's one way to get that data.