What is Do Not Track (DNT)?
Do Not Track is an HTTP header a browser can send to signal that the user does not want to be tracked. Proposed in 2009 and standardised loosely, it was never legally binding and was ignored by most of the industry. Its enforceable successor is Global Privacy Control, which California regulators have confirmed must be honoured.
Why it failed
DNT expressed a preference with no obligation attached. Sites were free to ignore it, and nearly all did.
It then developed a second problem: because so few browsers sent it and so few sites honoured it, the header itself became a distinguishing characteristic — a bit of entropy that made a browser slightly more identifiable to fingerprinting. A privacy signal that made you easier to recognise. Firefox and Chrome have since removed the user-facing setting.
Global Privacy Control
GPC is the working replacement. The difference is legal force rather than technology: under California’s privacy law it is recognised as a valid opt-out of the sale or sharing of personal information, which means honouring it is an obligation rather than a courtesy.
Several other jurisdictions have adopted or proposed similar recognition. The signal now travels with a rule behind it, which is what DNT never had.
Honouring it anyway
A tool that collects no personal data has nothing to opt out of, so neither signal changes what it does. Respecting the preference is still the right default — a visitor asking not to be measured has made a clear request, and the cost of honouring it is one uncounted visit.
sonex supports this explicitly. Set data-do-not-track="true" on the script tag and visitors sending a DNT signal are skipped entirely: no event is sent, nothing is recorded, and they do not appear in your numbers. It is opt-in because it is your decision to make about your own audience, not a default we should impose on your reporting.