Super cookies continue tracking users even if they think they have deleted their digital footprints.

Verizon Wireless said today that it will allow users to opt out of being tracked by so-called "super cookies."

A Verizon spokeswoman said the company expects to add an opt-out provision "soon."

At issue are tracking cookies intended to serve up relevant ads. The practice is nothing new for Web users, but as the Electronic Frontier Foundation noted last year, "super cookies" focus on mobile surfing and users cannot easily opt out.

"It allows third-party advertisers and websites to assemble a deep, permanent profile of visitors' web browsing habits without their consent," the EFF said at the time. "In fact, it functions even if you use a private browsing mode or clear your cookies."

In November, AT&T said it would phase out the use of super cookies. Verizon, however, has been under pressure for not doing the same, until now.

"Verizon takes customer privacy seriously and it is a central consideration as we develop new products and services," Verizon said today. "As the mobile advertising ecosystem evolves, and our advertising business grows, delivering solutions with best-in-class privacy protections remains our focus."

"We listen to our customers and provide them the ability to opt out of our advertising programs," Verizon continued. "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."

The tracking tech is included in an HTTP header called X-UIDH, EFF said, but unlike traditional Web cookies, the X-UIDH "is tied to a data plan, so anyone who browses the Web through a hotspot, or shares a computer that uses cellular data, gets the same X-UIDH header as everyone else using that hotspot or computer."

"That means advertisers may build a profile that reveals private browsing activity to coworkers, friends, or family through targeted advertising," the organization said.

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Verizon Wireless to Make 'Super Cookie' Tracking Opt Out