Do Not Track (DNT) is a browser signal — transmitted as an HTTP header (DNT: 1) — indicating a user's preference to opt out of behavioral tracking across websites. Proposed by the W3C and supported by major browsers from around 2011, DNT aimed to let users communicate a universal opt-out without interacting with individual consent banners. Unlike Global Privacy Control (GPC), DNT was never backed by legal requirement — no law obligated websites to honor it, and most ignored it. Major browsers including Safari, Firefox, and Edge deprecated DNT support by 2023. GPC supersedes DNT as the legally enforceable modern equivalent under CCPA.