AT&T Mobility, the nation's second-largest cellular provider, will no longer attach hidden Internet tracking codes to data transmitted from its users' smartphones.
The practice made it close to impossible to hide its subscribers' identities online, according to the Associated Press.
The change was made to remove a hidden string of letters and numbers that are passed along to websites that a consumer visits. It can be used to track subscribers across the Internet, a data-mining opportunity for advertisers that could still reveal consumer's identities based on the sites they went to, according to the AP.
Verizon Wireless announced on Friday it still uses this type of tracking, known as "super cookies." A company spokeswoman said business and government customers don't have the code inserted, however.
"As with any program, we're constantly evaluating, and this is no different," Debra Lewis said, according to the AP report.
Lewis added that consumers can ask that their codes not be used for advertising tracking, but that still passes along the codes to websites. Codes are even passes along if subscribers say they don't want their data being used, according to Lewis.
No evidence has been revealed indicating that Sprint and T-Mobile use such codes.
Tracking codes are part of the latest plan by the cellular industry to keep up with its users and their devices. Though codes don't contain personal information, they send information to websites alongside personal details that a user may submit voluntarily, such as a name or a phone number.
AT&T said its tracker was part of a testing project that's not used anymore.
"This is more like a license plate for your brain," said Jacob Hoffman-Andrews, a senior staff technologist with the Electronic Frontier Foundation, a civil liberties organization that opposed the practice, according to the Associated Press. "Everything you wonder about, and read, and ask the Internet about gets this header attached to it. And there are ad agencies out there that try to associate that browsing history with anything that identifies you."
Publications like Wired and Forbes reported in October that Verizon and AT&T were inserting the tracking numbers, even if their subscribers wanted to opt out.
The Wall Street Journal reported last week that the U.S. Marshals Service was flying airplanes above cities in the U.S. to collect certain cellphone information from criminals while also gathering data from innocent people.
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