Third-party cookie deprecation refers to the industry-wide phase-out of browser-based files used to track users across different websites. While initially planned as a total removal by Google Chrome, the strategy has shifted toward giving users explicit control over their browsing data. This transition forces marketers to move from individual tracking to privacy-centric measurement and first-party data strategies.
What is Third-Party Cookie Deprecation?
Third-party cookie deprecation is the process of eliminating the use of cookies set by domains other than the one a user is currently visiting. These cookies have historically powered cross-site tracking, behavioral targeting, and attribution.
The timeline for this process has changed significantly. While a full phase-out was expected by early 2025, Google announced on July 22, 2024, that it would not phase out third-party cookies on Chrome as originally planned. Instead, Google will introduce a new experience in Chrome allowing users to make an informed choice about their privacy settings that applies across their web browsing.
Why Third-Party Cookie Deprecation matters
This shift impacts how the digital ad economy functions, particularly for Chrome users who represent over 67% of the global browser market.
- Revenue Risks for Publishers: Without third-party cookies or alternative solutions, programmatic revenue for Google Ad Manager publishers could drop by 34%.
- Reduced Targeted Ad Value: Research indicates an 18% drop in ad impression prices when cookies are not used for tracking.
- Measurement Challenges: Advertisers face difficulties with conversion tracking, as 70% believe deprecation will hinder digital advertising progress.
- Infrastructure Shocks: Industry leaders compare removing the cookie to removing the roadways of a city, requiring substantial time to build viable alternatives that support a free internet.
How Third-Party Cookie Deprecation works
Deprecation occurs through browser-level changes that block or limit the functionality of cross-site cookies. Instead of a hard block for everyone, the current model emphasizes "user choice."
- User Choice Prompt: Chrome intends to introduce a prompt where users select their tracking preferences.
- Privacy Sandbox Adoption: Google will use its Privacy Sandbox APIs (like Topics and Protected Audience) to support advertising use cases without individual tracking.
- Partitioned Storage: Technologies like CHIPS (Cookies Having Independent Partitioned State) allow developers to opt cookies into partitioned storage, keeping them separate for each top-level site.
- Signal Substitution: Platforms like Google Ads will use a combination of AI-powered modeling and first-party data to fill the gaps left by missing cookie signals.
Best practices
To maintain campaign performance, marketers must adopt durable solutions that do not rely on third-party tracking.
- Build first-party data assets: Collect data directly from customer interactions. This is essential as 73% of customers expect businesses to understand their individual needs.
- Prioritize contextual advertising: Targets ads based on the content a user is currently viewing. Surveys show 79% of consumers are more comfortable with contextual ads than behavioral ones.
- Implement server-side tagging: Move tracking from the user's browser to a secure server you control. For example, financial services company Square improved conversion tracking by 46% using this method.
- Use Data Clean Rooms: These secure environments allow parties to collaborate on aggregated data. Currently, 64% of companies leveraging privacy-preserving tech use clean rooms.
- Audit current cookie usage: Use tools to identify which site functions rely specifically on third-party cookies to prevent site breakage.
Common mistakes
Mistake: Pausing privacy-first strategies because Google "reversed" the phase-out. Fix: Continue adopting Privacy Sandbox and first-party data. While cookies remain, user opt-out rates and browser restrictions still degrade cookie-based performance.
Mistake: Relying solely on the Privacy Sandbox for revenue. Fix: Diversify your strategy. Reports show publishers could lose 60% of Google Chrome revenue if they rely exclusively on the Sandbox compared to cookies.
Mistake: Ignoring user consent signals. Fix: Integrate with Google’s Consent Mode and the IAB Transparency and Consent Framework (TCF) to ensure measurement remains compliant with regulations like GDPR.
Examples
Example scenario (Measurement): An advertiser uses the Privacy Sandbox Attribution Reporting API to support billable metrics like CPA. This allows for conversion tracking after cookies are restricted.
Example scenario (Audience Exclusions): An advertiser excludes specific customer lists from a remarketing campaign. Google Ads and Display & Video 360 support this through the Privacy Sandbox, which delivered support for negative interest group targeting in Q3 2023.
Example scenario (Interest Targeting): Using the Google Topics API to serve gym equipment ads to users classified under the "sports" topic, rather than tracking their specific visit to a fitness blog. Note that some researchers found this API could be used to fingerprint 60% of users after only three observations.
FAQ
Is Google still removing third-party cookies? Google officially changed its plan in July 2024. It no longer intends to deprecate third-party cookies entirely. Instead, it will introduce a system where users choose their tracking preferences.
How will frequency management work without cookies? Google Ads and Display & Video 360 will use alternative identifiers like Publisher-Provided IDs, Exchange-Provided IDs, or Identifiers for Advertising (IFA). If no identifiers are present, platforms will use AI-powered modeling to manage how often a user sees an ad.
What is the Privacy Sandbox? It is a Google-led initiative to create technologies that protect user privacy online while providing tools for digital businesses. It includes APIs like Topics (for interest-based ads) and Protected Audience (for remarketing).
Will brand safety controls still function? Yes. Google Ads will continue using content types, digital content labels, and sensitive content exclusions. For post-bid solutions, a Protected Audience API feature allows signals to be passed to third-party ad tech vendor creative wrappers.
Does third-party cookie deprecation affect billable metrics like CPC? Ad interactions like clicks and views are not impacted by the phase-out. However, conversions tracked specifically by third-party cookies will shift to using the Privacy Sandbox Attribution Reporting API.
What is the difference between first-party and third-party cookies? A first-party cookie is set by the website a user is visiting to remember sessions or settings. A third-party cookie is set by a different domain (like an ad tech provider) to track the user across multiple different websites.
