Verizon will let its users opt out of so-called “supercookies” after complaints from privacy advocates.

The supercookies track online activities of users, and there was a tremendous amount of concern about what they were used for when it was discovered that Verizon and AT&T was keeping tabs on browsing by its users, according to a CNET report.

Verizon uses the data to analyze the interests of users through their online activities, which can then be passed on to advertisers to allow them to launch more targeted ads.

However, privacy advocates have slammed the supercookies, alleging that they could be used by hackers to track the activities of individuals, and they are difficult to get rid of unlike regular cookies, which can be deleted from a browser. Getting rid of a supercookie requires a user to unsubscribe from Precision Market Insights in Verizon’s Wireless Web portal, or through its mobile app.

Verizon, in response to the outcry, said it is trying to figure out a way that people can opt out of the supercookies, saying that it takes customer privacy seriously and is in fact a “central consideration” as new products are developed, according to the report.

Verizon said it never shares customer information with third parties. It had attempted to allay concerns about the supercookies — formally called Unique Identifier Headers (UIDH) — by saying that it changes the UIDH on a regular basis to protect users’ privacy, and that it does not share browsing activity with advertisers.

However, privacy advocates have criticized Verizon for failing ot be up front about its use of supercookies and also because it didn’t provide an option for users to opt out of them.

They also claim that Verizon’s advertising partner, Turn, has been using tracking headers to re-identify users and then reinstall cookies in their browsers, even after the user tries to opt out, which advocacy group Electronic Frontier Foundation called an “egregious violation of users’ expectations of privacy,” according to the report.