The proposal would have required that online advertisers submit their information to the FTC, which would compile a machine-readable list of the domain names used by those companies to place cookies or otherwise track consumers.
[11] In July 2009, researchers Christopher Soghoian and Sid Stamm implemented support for the Do Not Track header in the Firefox web browser via a prototype add-on.
[20] In January 2019, the W3C Tracking Protection Working Group was disbanded, citing "insufficient deployment of these extensions" and lack of "indications of planned support among user agents, third parties, and the ecosystem at large".
[33] Very few advertising companies actually supported DNT, due to a lack of regulatory or voluntary requirements for its use,[34] and unclear standards over how websites should respond to the header.
[35] Despite offering the option in its Chrome web browser, Google did not implement support for DNT on its websites, and directed users to its online privacy settings and opt-outs for interest-based advertising instead.
[36] The Digital Advertising Alliance, Council of Better Business Bureaus and the Data & Marketing Association does not require its members to honor DNT signals.
In addition, laws such as the European Union's General Data Protection Regulation (GDPR) have imposed restrictions on how companies are to store and process personal information.
[36][3] Princeton University associate professor of computer science Jonathan Mayer, who was a member of the W3C's working group for DNT, argued that the concept is a "failed experiment".