Online privacy advocates discovered in 2014 that network carrier Verizon is injecting tracking codes into most of its mobile web traffic, these were called Zombie cookies. Recently, the company is planning to use the same codes to target personalized ads from AOL, a company it has acquired early this year.
Verizon announced this plan on a privacy notice posted on its website, saying, "These programs use online and device identifiers, including AOL browser cookies, ad IDs from Apple and Google, and one created by Verizon, known as a Unique Identifier Header."
Unique Identifier Header (UIDH) is a code inserted into all unencrypted traffic flowing through Verizon's network. The code can be used by any website or advertising network whenever a user connects. Verizon itself did not promote UIDH as a tool that other companies can use. However, ProPublica, a non-profit news outfit, discovered that one ad company called Turn used UIDH to their advantage.
Verizon said that it will cease inserting these zombie cookies into all traffic. Instead, the company will limit its use to Verizon-owned websites and its partners. A Verizon spokesperson told Wired, "The UIDH will be sent only to Verizon companies, including AOL, and to a select set of other companies that help Verizon provide services."
When Verizon acquired AOL for $4.4 billion, several online privacy advocates said that it is for the purpose of using AOL's vast network to peek into customer browsing cookies and probably sell it to advertising companies.
In January, Verizon promised that it will allow its customers to opt out of the zombie cookie tracking program.