A third-party cookie is a tracking cookie placed on a user’s browser by a domain other than the website they are visiting, typically used for cross-site tracking, advertising, and retargeting. If you ever searched for a shirt on a clothing site and the same shirt (and other ones like it) appear in display ads on other websites, it’s because advertising services or brands are using third-party data to retarget you through programmatic advertising based on your prior online activity.
Information provided by third-party cookies are used to target consumers with ads based on consumer interests and browsing history gathered from website searches and browser activity. These third parties, like ad servers and social media sites, track information by enabling ads to retarget prospective customers as they move from site to site. If you didn’t purchase that shirt, third parties will remind you of it in the hopes that you’ll buy it.
For example, say you click on a pop-up video advertisement that appears on YouTube that leads them to another website. A third-party cookie collects that engagement data through a breadcrumb and sends it back to YouTube, so it understands a consumer’s browsing habits outside of its own website.
Third-Party Cookies and Data Privacy
Concerns about data privacy are central to the third-party cookie debate. Some users aren’t comfortable with advertisers knowing their search habits and will use ad blockers to eliminate third-party targeting. Users may even receive spam emails because their contact information has been acquired from organizations that sell third-party customer data.
Depending on the browser being used, users can clear out cookies after visiting a website. In the Chrome browser, users can select “History,” then “Clear browsing data.” From there, users can choose to delete browsing history, cookies, cached images, site settings and more.
Google announced its intention to phase out cross-site tracking (via third-party cookies) in Chrome browsers by the end of 2023. Other companies, like Apple, are also making a commitment to eliminate this tracking technology across channels and devices.
This means that users will have more of a say in how their data is being captured and shared. Data management and consent is becoming top-of-mind for some companies. Under evolving data privacy regulations, websites must ask for your permission before storing your data. Tech companies are also making it a priority to be more transparent about data privacy. Still, other companies will continue to track users with different technology—such as cookieless tracking methods—even without third-party cookies.
Learn more about the uses and impact of first-party, second-party and third-party data here.
FAQ
What is the difference between first-party and third-party cookies?
First-party cookies are set by the website you are currently visiting and are used to remember preferences, login sessions, and shopping cart contents. Third-party cookies are placed by a different domain than the one you are browsing, typically by advertising networks or social media platforms, and are used to track your behavior across multiple websites for ad targeting and retargeting purposes.
Why are third-party cookies being phased out?
Third-party cookies are being deprecated due to growing privacy concerns and regulatory pressure from laws like GDPR and CCPA. Major browser vendors, including Apple (Safari) and Mozilla (Firefox), have already blocked third-party cookies by default, and Google has announced plans to phase them out in Chrome. This shift is pushing the industry toward privacy-preserving alternatives such as first-party data strategies, contextual advertising, and consent management frameworks.
How can marketers adapt to the loss of third-party cookies?
Marketers are shifting toward first-party data collection, building direct relationships with customers through loyalty programs, newsletters, and authenticated experiences. Customer data platforms help by unifying first-party data from multiple touchpoints into comprehensive customer profiles that support personalization without relying on cross-site tracking. Contextual advertising, server-side tracking, and privacy-compliant identity solutions are also emerging as effective alternatives.
Related Terms
- Second-Party Cookie — Partner-shared data alternative as third-party cookies are deprecated
- Zero-Party Data — Voluntarily shared customer data that replaces third-party tracking
- Data Clean Room — Privacy-safe environment for audience matching without cross-site cookies
- Tag Management — Systems that deploy and control the tracking tags behind cookie collection