End of third-party cookies: what impacts?

In recent years, third-party cookies have been used to collect user data across websites. However, an increasing number of regulations now limit or even eliminate their use. This removal will have a significant impact on the online advertising industry. Nearly 8 out of 10 marketing and customer experience teams say they are dependent on third-party cookies.

What are third-party cookies?

Third-party cookies are files placed on a user’s computer, smartphone, or tablet by a server from a domain other than the site being visited. They are usually placed by audience measurement services, ad networks, or advertising platforms.

Third-party cookies enable tracking users as they browse multiple websites. They support behaviour analysis and help adjust marketing strategies.

They differ from first-party cookies (also called owner cookies), which are associated with the domain of the web page being visited.

Key dates in the phase-out of third-party cookies

2017: third-party cookies were deleted after 24 hours
2018: GDPR introduced explicit consent requirements for all personal data processing; third-party cookies began being blocked by Safari and Firefox
2020: Google announced the end of third-party cookies for 2022 (later pushed to 2024), and Apple required explicit in-app consent
2022: beta tests began for Privacy Sandbox, a proposal to support cross-site use cases without third-party cookies

Why are third-party cookies being phased out?

The progressive removal of third-party cookies is primarily due to increasing privacy concerns:

Privacy protection: 72% of internet users say they are concerned about web tracking for advertising; more than half now refuse cookies or change preferences to limit tracking; 82% expect brands to do the same, and 79% fear being monitored
Retargeting: this technique serves ads to users who visited a site without completing a purchase, encouraging them to return and convert

Over time, third-party cookies have also become less reliable due to:

ad blockers in web browsers
shared browsers in households
cache clearing

Advertisers report that third-party data often lacks precision and exclusivity. They also cannot verify its origin, age, or accuracy, so data quality has been inconsistent.

Finally, removing third-party cookies aims to reduce tracking by advertising actors and replace it with methods that better protect user privacy.

Consequences for advertisers and publishers

Online advertising has long relied on:

third-party cookies
building user profiles

In this context, advertisers must:

find new ways to target consumers
find new ways to measure campaign performance, such as media mix modeling, A/B testing, or data-driven attribution
enhance transparency and trust with users

56% of advertisers feel heavily impacted by the cookieless and consentless shift, and only 25% feel minimally affected.

What slows adoption of cookie alternatives?

limited reach of alternatives
advertisers’ maturity on the topic
lack of urgency
resources needed to launch tests

Consequences for users

For users, the end of third-party cookies means:

fewer targeted ads
better data privacy
stronger personal data protection, with explicit consent required
less exposure to advertising messages

Alternative solutions

The end of third-party cookies does not mean users will never be tracked online. Advertising ecosystem actors can still use alternative technologies to:

track navigation and visitor behaviour
target users for advertising

We are moving from a single universal solution (third-party cookies) to a variety of possible solutions that adapt to different situations.

First-party cookies

First-party cookies are set, with user consent, by the server of the visited site. They allow the site owner to store personalization and session data, helping identify returning visitors.

Strengths:
First-party cookies give brands greater accuracy in their relationships with publishers and work across all browsers.

Limitations:
They only work within a single domain. A publisher with multiple unrelated sites cannot recognise the same user across them.

Workarounds include using:

URL calls on the advertiser’s domain
subdomain delegation techniques like CNAME cloaking

Both approaches help bypass browser blocks by leveraging internal cookie data.

Fingerprinting

Fingerprinting aims to distinguish unique visitors using “weak” signals (browser, operating system, screen resolution, etc.). This allows brands to:

serve interest-relevant messages
retarget when appropriate
control ad exposure frequency

Alternative tracking technologies

Contextual targeting

Here, the goal is to use page content to reach relevant audiences without personal data or consent. Techniques include:

page classification by topic
artificial intelligence (computer vision, audio recognition)
keyword analysis
panels
semantics

Encrypted individual identifiers

Publishers assign a visitor ID using hashed and encrypted CRM data (usually email). This creates unique identifiers without revealing user identity.

Universal IDs help with:

targeting and retargeting
managing ad pressure
measuring campaign performance

However, adoption by brands is still limited, and many solutions are siloed and not interoperable.

Cohort-based solutions

Cohorts group thousands of people with shared attributes, such as:

behavioural affinity
interests
demographic criteria

When cohort impressions are shared, they are linked to segments rather than individual IDs. Benefits include:

increased reach
high precision
protection of personal data

Data clean rooms (DCR)

Data clean rooms allow two partners to match their first-party data without sharing raw data. This enables:

richer audience insights
refined segmentation
activation in advertising platforms

All of this happens without cookies and in an automated way.

Final thoughts

The end of third-party cookies marks the close of an era in which user data was insufficiently protected. While alternatives exist, none are yet a perfect replacement.

Google plans to remove third-party cookies in Chrome in 2024.

Cookieless alternatives from Dataventure

If you want to implement GDPR-compliant traffic generation or customer acquisition operations, Dataventure can support your project with its PRM consulting solution. It offers a wide choice of cookieless alternatives: