A third-party cookie is a small packet of data stored in a browser and generated, updated, and read by a website other than the domain in the address bar. A first-party cookie is handled by the domain the visitor is using. That difference matters when a brand tries to understand activity beyond its own website. section 6.2 section 1.1
Third-party cookies have supported cross-site tracking, online advertising, and analytics. But browser restrictions and consumer demands for control can leave gaps in that data. Marketers should not treat a once-reliable cross-site view as a complete customer picture. section 1.1 section 1.7
The practical choices are not simply “keep cookies” or “lose measurement”:
- Account for browser differences: Safari and Firefox block third-party cookies by default; Chrome’s previously planned full deprecation did not proceed as announced in July 2024. section 1.1 section 2.1
- Build insight from direct brand interactions and first-party identifiers, while making transparency and consent part of the strategy. section 1.1 section 1.7
- Evaluate privacy-focused alternatives without assuming they reproduce individual cross-site tracking: Privacy Sandbox initiatives such as Topics and FLEDGE use aggregated or on-device data. section 2.1
A visitor before sign-in
An anonymous visitor may choose a flight before signing in. Cookie-based tracking can help connect that prelogin activity to the account later. This illustrates why continuity matters to a business, but it does not mean a third-party cookie is required: the distinction depends on which domain generates, updates, and reads the cookie. section 6.2
