🔗 "Do Not Track" HTTP header supported by IE, Opera, FF, Safari but not Chrome

Do Not Track (DNT) was a proposed HTTP header field, designed to allow internet users to opt-out of tracking by websites—which includes the collection of data regarding a user's activity across multiple distinct contexts, and the retention, use, or sharing of data derived from that activity outside the context in which it occurred.

The Do Not Track header was originally proposed in 2009 by researchers Christopher Soghoian, Sid Stamm, and Dan Kaminsky. Efforts to standardize Do Not Track by the W3C in the Tracking Preference Expression (DNT) Working Group did not make it past the Candidate Recommendation stage and ended in September 2018 due to insufficient deployment and support.Mozilla Firefox became the first browser to implement the feature, while Internet Explorer, Apple's Safari, Opera and Google Chrome all later added support.

DNT is not widely adopted by the industry, with companies citing the lack of legal mandates for its use, as well as unclear standards and guidelines for how websites are to interpret the header. Thus, it is not guaranteed that enabling DNT will actually have any effect at all. The W3C disbanded its DNT working group in January 2019, citing insufficient support and adoption. Apple discontinued support for DNT the following month.