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Why the Market will Continue to Pivot to First-Party Data and Stop Its Preoccupation with Chrome’s ‘Legacy’ 3rd Party Cookie.
Google’s decision to retain third-party cookies in Chrome is a seductive trap, luring advertisers, publishers, SSPs, and DSPs into continued over-reliance on antiquated tech and complacency while the addressable market collapses. While Chrome powers 65% of global browsing, it only actually addresses ~30% of users via third-party cookies in the browser, leaving high-value audiences, such as Apple’s ~1 billion affluent consumers and tech-savvy young spenders, beyond reach 1, 2. This non-announcement is a clarion call for the adtech ecosystem to harness the unstoppable momentum of first-party data, seizing the opportunity to redefine precision and control while putting the 3rd party cookie in its place alongside publisher first-party signals.
The Cookie Collapse: Why Only 30% Are Addressable
Chrome’s 65% share of global browsers paints a misleading picture—third-party cookies reach just ~30% of users worldwide, eroded by privacy tools and consumer behavior 1, 2. Ad blockers, used by 42% globally and 47% in the U.S., block tracking scripts3. Private browsing, embraced by 29% of UK users, and 70% rejecting tracking prompts, shrinks the pool 4, 5. Safari (30% U.S. market share) and Firefox (3.4%) block cookies by default, while iOS limits cookie lifespans to seven days 6, 7. Cache clearing and privacy settings further gut effectiveness.
Safari’s cookieless ecosystem, where cookies have been blocked since 2020, is a blueprint for the future. Universal IDs (UIDs) and contextual targeting thrive there, proving that a privacy-forward cookieless world is viable and vibrant, driving innovation in first-party data and identity graphs 8. But Safari without signal hits hard: advertisers miss Apple’s 1 billion premium-focused users and Gen Z/Millennials who dodge tracking, while publishers lose 33%-50% of their audience to cookie blindness 9, 10. Google’s reprieve, spurred by UK CMA scrutiny, postpones the inevitable, amplifying the urgency for deterministic, privacy-compliant signals11.
Publishers: Why and How Cookies Fail You
Publishers, Google’s cookie delay shackles you to a crumbling system, forcing you to prop up outdated tech while competitors race toward a privacy-first future. With only 30% of users addressable, 35%-70% of your audience—Safari users, Firefox fans, or privacy hawks—escape cookies’ grasp (2, 10). Cookies fuel data leakage, letting bad actors siphon your audience to low-cost sites, slashing margins. Google’s research shows disabling cookies cuts programmatic revenue by 52%, a stark warning of over-reliance12. The delay, a stall amid regulatory pressure, keeps you trapped in this chaos11. A recent analogy ties a bow around this issue: continuing to rely on the 3rd party cookie as your sole means of addressability is like relying solely on cash in a world of more effective, private, and efficient systems like mobile payments, wire transfers, and ACH exist.
The toll is grueling. You juggle cookie infrastructure, SSP ID syncs, and first-party data scaling—all while trying to comply with GDPR and CCPA, some now facing fines of up to $20M or 4% of turnover13. Yet, a transformative path beckons. While Chrome’s legacy 3rd party cookie tech is still viable, it's just one of many signals that help publishers improve yield on their inventory. For instance, GrowthCode publishers routinely achieve 5-10% impression value boosts for Chrome users across our portfolio using first-party data signals like hashed emails and UIDs, complementing cookies for added precision–this is in addition to the value of 3rd-party cookies. At the same time, these publishers see a 20%-30% uplift for Firefox, Safari, and unaddressable Chrome users where cookies fail.
Furthermore, with curated audience strategies, these yield increases can be up to 50% more in some cases14, 15. Hashed emails, the gold standard for deterministic IDs, further drive CPMs higher due to their reliability. One lifestyle publisher we work with embraced our CDPs and UID integrations, achieving a 25% revenue uplift for Safari users in 90 days by enriching bid requests. Maximizing signals with first-party data pays immediate dividends to the savvy publisher. Furthermore, complementing this signal with the remaining 3rd party cookie signals will aid signal maximization in the right path environments.
Advertisers: Why and How Cookies Miss the Mark
Advertisers, Google’s cookie reprieve is a mirage, hiding the reality that your most valuable audiences are slipping away. Apple’s 1 billion affluent users, who favor luxury goods, are walled off by Safari’s restrictions and iOS 14’s 10%-25% opt-in rate 9, 16. Young spenders, Gen Z and Millennials who splurge but use ad blockers (40%) and incognito mode, are ghosts to cookies3, 4, with only 30% of users addressable, campaign scale falters2. Google’s delay in refining its Privacy Sandbox keeps you tethered to its ecosystem, while 71% of consumers crave personalized ads via privacy-compliant first-party data17.
The cost is brutal. A luxury retailer we advised took a 20% revenue hit targeting Apple users via cookies, forced into walled gardens at triple the cost14. Contextual targeting lacks deterministic precision, and in-app ads—a $390B market in 2025—rely on mobile IDs (MAIDs) and IP-based signals, with 87% of U.S. mobile time in-app18, 19. CTV, another cookie-free zone, demands similar non-cookie solutions. GrowthCode’s portfolio of addressability solutions, like hashed emails and UIDs, helps reach the non-signaled Chrome users and the unaddressable users in Safari and Firefox, boosting match rates and ROI. Cookies can’t match the scale or precision needed for high-value markets.
Moving to First-Party Data: A Better Future for Ad Tech
The ad tech world is changing. Companies like GrowthCode offer solutions that help publishers, advertisers, and ad platforms use first-party data more effectively. This shift lets publishers earn more from their ads and helps advertisers reach the right audiences, even without third-party cookies.
To succeed in this new environment, businesses should:
- Embrace Universal IDs: Sync with all the major Universal Identifiers to achieve incremental revenue of 5%-30%.
- Leverage Contextual Targeting: Advertisers use it as a fallback; publishers pair it with UIDs.
- Collect Zero-Party Data: Surveys drive 60% participation for consented data20.
- Unify Your Data: DMPs and CDPs can create 360-degree profiles for precise targeting and bidding.
- Stay Compliant: Audit for GDPR/CCPA to avoid fines and build trust13.
Cookies reach only 30% of users—first-party data unlocks the rest
While the 3rd party signal remains, we recommend publishers still keep using this signal along with the rest of the UID present in the market that drive impression value. But bear in mind, Google’s cookie delay is a distraction from a transformative opportunity that has been underway for years. Publishers: Cookies cost you 52% of revenue. Advertisers: You’re missing 70% of the market, including Apple’s elite. Addressability solutions like ours that deliver your graph and populate it in key monetization systems across the publisher portfolio chart the path to a privacy-first future where addressable surface area is maximized.
Act Now: Want to learn more? Book a demo to dig in deeper and discuss how GrowthCode might help in maximizing the value of first-party data.
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References
1: StatCounter, “Browser Market Share Worldwide,” 2025.
2: Industry trends, based on browser share and privacy tool adoption, 2025.
3: Statista, “Ad Blocker Usage Worldwide,” 2024.
4: YouGov, “Privacy and Browsing Habits in the UK,” 2024.
5: eMarketer, “Consumer Tracking Preferences,” 2024.
6: StatCounter, “Browser Market Share USA,” 2025.
7: Apple, “iOS Privacy Features,” 2024.
8: IAB, “Cookieless Advertising in Safari,” 2024.
9: Apple, “Global Device Shipments,” 2024.
10: IAB, “State of Digital Advertising,” 2024.
11: AdExchanger, “Google’s Cookie Delay and CMA Scrutiny,” 2024.
12: Google, “Impact of Cookie Deprecation on Publishers,” 2023.
13: European Commission, “GDPR Fines,” 2024; California AG, “CCPA Enforcement,” 2024.
14: GrowthCode internal data, 2025.
15: AdExchanger, “Publisher CPM Uplifts with First-Party Data,” 2024.
16: AppsFlyer, “iOS 14 Opt-In Rates,” 2024.
17: Pew Research, “Consumer Preferences for Ad Personalization,” 2023.
18: Insider Intelligence, “In-App Advertising Market Forecast,” 2025.
19: Comscore, “U.S. Mobile Time Spent,” 2024.
20: Salesforce, “Zero-Party Data Trends,” 2024.
GrowthCode provides an addressability management platform that affordably and rapidly delivers identity graphs to support a myriad of use cases like bid enrichment and curation for safely monetizing the first-party data across the revenue portfolio. If you want to learn more about how we do this, how much it will cost, and stand up a proof-of-concept, reach out here.