AT&T says it's no longer inserting phone-tracking IDs in web traffic, which was only a test, but may still sell the resulting data
AT&T Stops Using Undeletable Phone Tracking IDs — AT&T says it has stopped its controversial practice of adding a hidden, undeletable tracking number to its mobile customers' Internet activity.
Context & Ripple Effects
This story lands just weeks after ProPublica and Wired revealed that Verizon was running essentially the same play — injecting a unique, undeletable identifier into subscribers' web traffic with no opt-out. AT&T's admission that it too had been testing the technique confirms this was not a one-carrier experiment but an emerging industry practice.
It also sets up a longer arc of carrier data monetization coming under pressure: AT&T would later shut down its Internet Preferences deep-packet-inspection ad-targeting program, and Senator Wyden's probe into real-time location sales eventually forced all four major carriers to unwind those deals.
First-order effects
- AT&T mobile customers stop having an undeletable tracking ID inserted into their unencrypted web traffic going forward — though the framing as 'only a test' means the practice could resume, and any data already gathered remains in AT&T's hands.
- The critical caveat: AT&T signals it may still sell the data the test produced, so ending the insertion does not end the monetization of what was collected.
Second-order effects
- Verizon, exposed for the identical technique days earlier, now faces pressure to match AT&T's retreat or defend its own program alone — and both carriers learn that the politically vulnerable part is the visible traffic manipulation, not the underlying data business.
- Advertisers and ad-tech intermediaries who were beginning to treat carrier-injected headers as a persistent cross-site identifier lose confidence in the signal, pushing targeting back toward conventional cookies and first-party data.
Third-order effects
- If the pattern holds, carriers conclude that how they collect subscriber data matters more publicly than whether they profit from it — shifting the industry toward less visible forms of monetization (location sales, analytics partnerships) until regulators catch up, as they eventually did with the 2019 location-data wind-down.
- The episode helps establish a durable principle for the broadband era: network operators occupy a privileged position inside customer traffic, and self-declared 'tests' can become standing practices without consent — a structural argument that later feeds into privacy regulation and net-neutrality debates over what ISPs may do with the data crossing their pipes.
The trend: Carriers are learning to monetize their privileged view of subscriber activity while retreating from the most visible and indefensible collection methods under press and political pressure — a cat-and-mouse between ISP data businesses and privacy accountability that is still playing out.