Global Privacy Control (GPC)
Also known as: GPC
Global Privacy Control is a browser signal that automatically tells every website a visitor opts out of the sale or sharing of their personal data.
What it actually means
Global Privacy Control is a setting a person enables once in their browser or a privacy extension; from then on, every site they visit receives an automatic opt-out signal. Unlike a cookie banner choice made per site, GPC is universal — and in states like California and Colorado, honoring it is legally required, treated as a binding do-not-sell request. For advertisers this means a slice of traffic arrives pre-opted-out regardless of any consent prompt. Compliant tracking setups detect the GPC header and suppress data sharing for those visitors. It is a small but growing part of why measured numbers and real-world results increasingly diverge.
A few percent of your website visitors carry a GPC signal today. Your tracking should respect it automatically — the fine for ignoring it lands on you, not on the ad platform.
Related terms
Consent mode adjusts how tracking tags behave based on a visitor's cookie-consent choice, using modeled data to fill gaps when tracking is declined.
A third-party cookie is a tracking file set by a domain other than the site being visited, historically used to follow people across the web.
First-party data is information you collect directly from your own customers and prospects, such as email addresses, phone numbers, and purchase history.
iOS 14's App Tracking Transparency requires apps to ask users for permission before tracking them, which sharply reduced the data Meta can use for ad targeting and measurement.
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