Cookie
A small text file stored in a user's browser by websites, used for tracking, personalization, and ad targeting.
What Cookie means
Cookies are small data files stored in users' browsers that enable website functionality, user tracking, and ad targeting. First-party cookies are set by the website being visited, while third-party cookies are set by external services like ad platforms. Third-party cookies have been the backbone of cross-site tracking and retargeting, but their use is declining due to privacy regulations (GDPR requires consent, ePrivacy Directive mandates cookie banners) and browser restrictions (Safari's ITP, Firefox's ETP). Google Chrome has been gradually restricting third-party cookies through its Privacy Sandbox initiative. The deprecation of third-party cookies is fundamentally reshaping digital advertising, pushing the industry toward first-party data strategies, server-side tracking (CAPI), and contextual targeting.
Related terms
Consent
A user's explicit or implied permission for data collection, processing, or advertising targeting, required by privacy regulations.
First-Party Data
Data collected directly by an organization from its own customers and users through direct interactions.
Third-Party Data
Data collected by entities that have no direct relationship with the user, purchased or aggregated for advertising targeting.
Privacy Sandbox
Google's initiative to replace third-party cookies with privacy-preserving APIs for advertising targeting and measurement.