Third-party cookies are small text files placed by domains other than the website you're visiting, used to track your browsing behavior across the internet for advertising purposes. After years of announcements and reversals, third-party cookies are effectively dead: Safari and Firefox blocked them years ago, and Google Chrome—the last major holdout—has committed to giving users control over them. As of 2025, approximately 47% of all web traffic is already cookieless, and the advertising industry is rapidly adapting to a post-cookie world.
What Happened to Google's Cookie Deprecation Plan?
Google's cookie saga is one of the most dramatic reversals in tech history. In January 2020, Google announced it would phase out third-party cookies in Chrome within two years. That deadline was pushed to 2023, then 2024. In July 2024, Google reversed course entirely, announcing it would keep third-party cookies but add a new user choice mechanism.
Then in April 2025, Google effectively abandoned its Privacy Sandbox APIs, acknowledging that the replacement technologies (Topics API, Protected Audiences, Attribution Reporting) had failed to gain meaningful industry adoption. According to reporting by Digiday, fewer than 2% of programmatic advertisers had integrated Privacy Sandbox APIs by the time of the shutdown.
How Much of the Web Is Already Cookieless?
Despite the focus on Google Chrome, the cookieless future has already arrived for nearly half the internet. Apple's Safari browser (which holds approximately 20% of global market share) has blocked third-party cookies since 2020 via Intelligent Tracking Prevention (ITP). Mozilla Firefox (approximately 3% market share) blocks them by default through Enhanced Tracking Protection.
When combined with users who have manually disabled cookies and those using privacy-focused browsers like Brave, approximately 47% of global web traffic is already cookieless, according to StatCounter and browser market share data. In Europe, the figure is even higher: France's CNIL reports that 40% of French internet users refuse all cookies when presented with a consent banner.
What Technologies Are Replacing Third-Party Cookies?
The post-cookie advertising landscape is fragmenting into several competing approaches. No single technology has emerged as a clear successor, and most advertisers are adopting a combination of methods to maintain targeting capabilities.
Cookie Replacement Technologies Compared
| Technology | How It Works | Privacy Level | Accuracy | Adoption Status |
|---|---|---|---|---|
| First-party data | Direct data from user-brand relationships | High (consent-based) | Very high | Widely adopted |
| Contextual targeting | Ads matched to page content, not user profiles | Very high (no user data) | Moderate-high | Growing rapidly |
| Server-side tracking | Data collection moved to server infrastructure | Low (hidden from users) | High | Increasing |
| On-device matching | Ad selection happens locally in the browser | Very high (data never leaves device) | High | Emerging |
| Unified ID solutions | Shared identity frameworks (UID 2.0, RampID) | Medium (email-based) | High | Moderate adoption |
| Cohort-based targeting | Users grouped by shared interests | Medium | Moderate | Limited (Privacy Sandbox failed) |
Why Did Google's Privacy Sandbox Fail?
Google's Privacy Sandbox failed for several reasons. The Topics API was too broad for effective targeting (only 469 topics vs. millions of interest segments used in cookie-based targeting). Protected Audiences (formerly FLEDGE) was technically complex and added significant latency. Most critically, advertisers saw 30-60% drops in campaign performance during Privacy Sandbox testing, according to data shared by several ad tech companies at the IAB Tech Lab's 2024 conference.
The UK's Competition and Markets Authority (CMA) also raised concerns that Privacy Sandbox would consolidate more power with Google, since the APIs were designed to run in Chrome. This regulatory pressure contributed to Google's decision to retreat from mandatory cookie deprecation.
How Adreva Navigates the Post-Cookie World
Adreva was designed for a cookieless world from day one. Rather than trying to replicate cookie-based tracking with new technology, Adreva takes a fundamentally different approach: users declare their ad preferences directly, and ad matching happens on-device without any cross-site tracking. This means Adreva's effectiveness is completely independent of cookie availability, browser restrictions, or platform policies. As the rest of the industry scrambles to adapt, Adreva's privacy-by-design architecture already operates in the post-cookie paradigm.
Frequently Asked Questions
Are third-party cookies completely gone?
Not yet in Chrome, but effectively yes across the broader web. Safari and Firefox have blocked them for years. Chrome still supports them but is adding more user controls. Approximately 47% of web traffic is already cookieless, and that percentage grows monthly as more users adopt privacy tools and settings.
What are first-party cookies and are they affected?
First-party cookies are set by the website you're actually visiting and are used for essential functions like keeping you logged in, remembering your shopping cart, and storing preferences. These are not being deprecated and remain fully functional across all browsers. The deprecation only affects third-party cookies from external domains.
How does contextual targeting compare to cookie-based targeting?
Recent studies show contextual targeting performs surprisingly close to cookie-based behavioral targeting. A 2024 study by IAS found that contextual ads achieved click-through rates within 5-8% of behavioral ads, while driving higher brand safety scores. For some verticals like travel and finance, contextual targeting actually outperformed behavioral targeting.
Will advertising become less personalized?
Not necessarily. The industry is shifting from surveillance-based personalization (tracking you without consent) to consent-based personalization (you telling platforms what you're interested in). This approach—used by platforms like Adreva—actually delivers more relevant ads because users explicitly declare their interests rather than having them inferred from browsing behavior.
What should advertisers do to prepare?
Advertisers should invest in first-party data strategies, test contextual targeting campaigns, explore on-device ad matching solutions, and reduce dependence on any single tracking technology. The most resilient advertising strategies combine multiple approaches rather than relying on a single identity solution.
How does server-side tracking differ from cookies?
Server-side tracking moves data collection from the user's browser to the advertiser's or publisher's server infrastructure. This makes tracking invisible to browser-based privacy tools and ad blockers. While technically effective, privacy advocates argue that server-side tracking undermines the spirit of cookie deprecation by simply moving surveillance to a less visible location.