Privacy

Third-party cookies

Cookies set by a domain other than the site you are on, long used for cross-site ad tracking. Safari and Firefox block them by default. Chrome still allows them: Google dropped its removal plan and retired Privacy Sandbox in 2025.

How it's used

A retargeting campaign reaches Chrome visitors but misses most iPhone users browsing in Safari, so its reported results only describe part of the audience.

How I help

I build measurement that does not depend on third-party cookies: first-party data, server-side events, MMM and holdouts.

Common toolsWhy first-party data and server-side tracking matter