Cookie Deprecation
The phase-out of third-party cookies by web browsers, forcing a structural shift in ad targeting, retargeting, and cross-site attribution.
Cookie deprecation is the removal of third-party cookies from major web browsers — already complete in Safari and Firefox, and now enforced in Chrome through opt-in tracking prompts and IP Protection. The shift breaks traditional cross-site retargeting, shrinks measurable audiences, and forces marketers onto first-party data, identity resolution, and server-side tracking.
Definition
Cookie deprecation refers to the industry-wide removal of third-party cookies from web browsers. Apple's Safari has blocked third-party cookies by default since 2020 via Intelligent Tracking Prevention. Firefox has done the same via Enhanced Tracking Protection. Google Chrome — which commands roughly 65% of global browser share — shifted in 2024 from a planned full deprecation to a user-choice model and IP Protection in Incognito, with third-party cookie access materially degraded for advertising and attribution. The cumulative effect: cross-site identifiers that powered retargeting, view-through attribution, and frequency capping for two decades are gone or severely restricted.
What actually changed and when
Safari removed third-party cookies in 2020 with Intelligent Tracking Prevention. Firefox followed with Enhanced Tracking Protection. Chrome's plan evolved through 2024: rather than a hard deprecation, Google shifted to a user-choice model with opt-in prompts, introduced IP Protection for Incognito, and continued rolling out Privacy Sandbox APIs (Topics, Protected Audience, Attribution Reporting). The net effect for advertisers is the same as deprecation — third-party cookie signal is unreliable and shrinking.
Beyond browsers, iOS App Tracking Transparency (ATT) made mobile IDFA effectively opt-in in 2021, cutting its availability by 70% plus. Between ITP, ETP, ATT, and IP Protection, the long-running assumption that you can silently track a user across sites and apps is no longer valid.
What replaces third-party cookies
First-party data collected through your own properties — form fills, product usage, email engagement, website visits — becomes the strategic asset. Identity resolution stitches first-party data into unified profiles using deterministic identifiers like email. Server-side tracking (Google Tag Manager server-side, Segment, Snowplow) moves measurement off the browser entirely. For advertising, clean rooms (AWS, Google Ads Data Hub, LiveRamp) let you activate first-party data without exposing raw user identifiers.
For B2B specifically, the impact is smaller than for B2C because B2B identity has always leaned on work email and firmographic matching rather than cookies. The winners are B2B marketing teams that invest in visitor identification, CRM hygiene, and email-based audience activation on platforms like LinkedIn and Google Customer Match.
Why it matters
Cookie deprecation breaks the default B2C and B2B advertising stack. Retargeting pools shrink, CPMs rise for identifiable users, view-through attribution collapses, and multi-touch attribution models become unreliable. The winners are companies with rich first-party data, deterministic identity resolution, and server-side measurement. The losers are those still running programmatic campaigns against third-party audience segments.
Examples
- Safari's Intelligent Tracking Prevention blocking third-party cookies by default
- Chrome introducing IP Protection in Incognito and Privacy Sandbox APIs
- Firefox Enhanced Tracking Protection blocking cross-site trackers
- iOS App Tracking Transparency cutting IDFA availability by 70% plus
How Bullseye helps
Bullseye's identification is not dependent on third-party cookies. Matching happens against a first-party identity graph using email-based and deterministic signals, meaning visitor identification survives Safari ITP, Firefox ETP, Chrome IP Protection, and whatever comes next. You identify the same percentage of traffic in a cookieless world as you do today.
Frequently asked questions
What is cookie deprecation?
Cookie deprecation is the removal or restriction of third-party cookies by web browsers. Safari and Firefox already block them by default. Chrome shifted in 2024 to a user-choice model with IP Protection, effectively ending reliable cross-site tracking. The result is that cookie-based retargeting, view-through attribution, and programmatic audiences lose precision and scale.
When will third-party cookies be deprecated in Chrome?
Google moved away from a planned full deprecation in 2024 and instead introduced a user-choice model plus IP Protection in Incognito. In practice, third-party cookie signal in Chrome is already materially degraded, Privacy Sandbox APIs are live, and most advertisers are planning for a cookieless baseline regardless of Google's final policy.
How does cookie deprecation affect marketing?
Cookie deprecation shrinks retargeting pools by roughly 40% post-ITP, breaks view-through attribution, weakens multi-touch attribution models, and raises CPMs for addressable audiences. Marketers who rely on third-party audience segments, pixel-based retargeting, and click-path attribution see the biggest declines.
How do I prepare for a cookieless future?
Build a first-party data program: capture email, consented identifiers, and first-party behavior across your site. Invest in identity resolution and a CDP to unify profiles. Move tracking server-side (GTM server-side, Segment, Snowplow). Adopt email-based audiences on LinkedIn and Google Customer Match. For B2B, add website visitor identification that does not depend on third-party cookies.
Does cookie deprecation affect B2B marketing?
Yes, but less than B2C. B2B identity has always been anchored to work email and firmographic data, not anonymous cookie pools. B2B retargeting and programmatic on LinkedIn and cookieless ad networks already use email-based matching. The main impact on B2B is weaker website retargeting and attribution, which is solved by first-party visitor identification.
Related terms
Deanonymization
The process of identifying previously anonymous website visitors by connecting their browsing activity to real, known identity data.
First-Party Data
Data collected directly from your own customers and visitors through your own channels — website, product, email, CRM — making it the most accurate and privacy-resilient data type.
Identity Resolution
The process of stitching disparate identifiers — cookies, emails, devices, phone numbers, IP addresses — into a single unified profile of one real person.
Retargeting
A paid-media tactic that serves ads specifically to people who have already visited your website, engaged with your brand, or appeared in your CRM.
Keep learning
Related Use Cases
Lead Generation
Generate leads from your website without forms by identifying anonymous visitors.
Sales Intelligence
Real-time intelligence on website visitors for proactive sales outreach.
Account-Based Marketing (ABM)
Identify individuals from target accounts visiting your site for ABM programs.
Related Guides
Put cookie deprecation into practice
See how Bullseye helps with cookie deprecation and more.