WJS: Study Finds ‘Supercookies’ Used Outside U.S.

Bell Canada is one of the few carriers still using the evil 'supercookies' to track their customers. Thanks, Bell... Article by Elizabeth Dwoskin for WSJ Most major US wireless carriers are no longer using controversial identifiers that some researchers call “supercookies,” but their use appears to be extensive overseas.

That’s the conclusion of a study by privacy group Access Now, which tested how the technology is being used around the world. Supercookies, formally known as unique identifier headers, are virtually undeletable codes that track mobile users’ browsing habits.

Access Now looked for the headers in transmissions from 200,000 users in 164 countries who clicked on a button on a website it created, Amibeingtracked.com. The site launched in October 2014, and remains active. The sample was not representative.

The group said three out of the four major U.S. carriers — AT&T, T-Mobile, and Sprint — aren’t using supercookies. The fourth, Verizon Wireless, is using them; Access Now said. Verizon says it offers users an option to turn off the technology.

Outside the U.S., the group found large carriers, including Telefonica de Espana, Vodafone affiliates in Spain and the Netherlands, Bell Canada and Viettel Peru are using the headers. Overall, supercookies were detected in 10 countries, including China, India, Mexico, Morocco and Venezuela.

Privacy groups criticized AT&T and Verizon earlier this year for employing supercookies in initiatives that shared user data with marketing partners. Marketers are increasingly interested in user data from phones, as people spend more time on them.