Strategy & Tracking
Third-Party Cookie
A tracking cookie set by a domain other than the one you're visiting — the fading backbone of cross-site ad tracking.
Definition
A third-party cookie is a tracking file set by a domain other than the website a user is currently on, historically used to follow people across sites for advertising and measurement. As browsers phase them out, marketing is shifting to first-party data and server-side methods — a move often called "cookieless."
In depth
Third-party cookies powered much of the open web's ad targeting and attribution for two decades. They let advertisers recognize the same person across different sites, build audiences, and measure conversions after a click. That entire mechanism is now being dismantled by privacy regulation and browser defaults.
The fallout is practical: weaker cross-site retargeting, leakier conversion tracking, and attribution that no longer sees the full journey. The response is a shift to data you own — first-party data collected with consent — and to server-side tracking and platform tools like enhanced conversions that don't depend on third-party cookies.
Treating the cookieless shift as a distant problem is the real risk; the gaps are already here. We build measurement on first-party foundations now, so your tracking and targeting stay durable as the last third-party cookies disappear.
Strategy & Tracking
Want this run for you, not just read about?
Clean tracking and honest attribution, so you know which dollars actually produce revenue.