AT&T toyed around with a recipe for baking supercookies into the network layer of its mobile devices, although Verizon had already been discretely feeding the trackers to its subscribers.
Now Verizon, feeling the pressure, has finally agreed to stop the non-consensual tracking of its customers' web activities.
AT&T abandoned the use of supercookies a few months ago, but Verizon had been using the persistent tracking techniques for well over two years.
Supercookies, x-UIDH headers, are unique identifiers that are used to track mobile devices. Unlike locally stored cookies, which can be deleted, supercookies are injected out of reach at the network layer.
Verizon spokesperson Debra Lewis confirmed on Jan. 30 Verizon's decision to finally stop tailing its users on behalf of advertising platforms and marketing firms. Lewis said the leading wireless carrier in the United States takes privacy seriously, calling it a key consideration when Verizon develops new products.
"As the mobile advertising ecosystem evolves, and our advertising business grows, delivering solutions with best-in-class privacy protections remains our focus," Lewis said. "We listen to our customers and provide them the ability to opt out of our advertising programs."
"As a reminder, Verizon never shares customer information with third parties as part of our advertising programs," she added.
Lewis said her company never shares consumer data with Verizon's partners, as part of the business' advertising programs. She said Verizon listens to its customers and enables them to opt out of the company's advertising programs, although the supercookie exit isn't open just yet.
"We have begun working to expand the opt-out to include the identifier referred to as the UIDH, and expect that to be available soon," said Lewis.
While Lewis asserts that Verizon doesn't sell advertising information compiled via supercookies, privacy watchdogs and the Feds seem to disbelieve that assertion.
Electronic Frontier Foundation, a privacy watchdog group, believes Verizon has been selling information on user browsing habits to marketing firm Turn.
"New research shows Verizon's advertising partner, Turn, using these tracking headers to re-identify users and reinstall cookies on their browsers -- even after they've tried opting out of targeted ads or deleted their cookies. This is an egregious violation of users' expectations of privacy," said a petition from Electronic Frontier Foundation, a privacy watchdog group.
Back in November 2014 and just a few weeks after it was revealed to be using the persistent trackers, AT&T announced that it was ending its supercookie trials. It said it hadn't given up on establishing a system for targeted advertising but planned to offer subscribers the ability to opt-out.