Google Chrome Third-Party Cookie Deprecation - Impact on Digital Marketing

Third-party cookies are being deprecated from Google Chrome. This article outlines the steps you can take to reduce its impact on conversion tracking and retargeting.

On January 4th 2024, 1% of worldwide Chrome users had third-party cookies restricted. Whilst that is a small percentage, it represents roughly 30 million people and is the start of a significant change in digital marketing culminating in a complete restriction on third-party cookies by Chrome in the second half of this year.

If this sounds familiar, it’s because Chrome is not the first browser to do this, Safari did so in 2017 and Firefox in 2019. Chrome is the most popular web browser in the world and in the UK is used by 61% of desktop and 43% of mobile users. Its deprecation will have a bigger effect, so it’s important for advertisers to prepare accordingly.

Why is Google doing this?

Google's decision to block third-party cookies in Chrome is primarily motivated by increasing concerns about online privacy. Here are some key reasons behind this move:

  • Privacy Concerns: In recent years, there has been growing awareness and concern about how much personal data is tracked and collected by various online entities. Third-party cookies, which are created by domains other than the one the user is visiting, have been a significant tool for tracking users across the web. Blocking these cookies is seen as a way to enhance user privacy.
  • Regulatory Pressure: Governments and regulatory bodies around the world have been introducing stricter privacy laws (like GDPR in Europe and CCPA in California). These regulations often require more transparency and control over personal data. By eliminating third-party cookies, Google is aligning itself more closely with these regulations.
  • User Demand: Many internet users have become more privacy-conscious and are demanding greater control over their online data. By blocking third-party cookies, Google is responding to these user preferences.
  • Technological Alternatives: The ad industry and web technologies have evolved, creating alternatives to third-party cookies for ad targeting and measurement. Google has been working on initiatives like the Privacy Sandbox, which aims to develop more privacy-preserving alternatives to track users for advertising purposes.
  • Competitive Reasons: With other major browsers like Safari and Firefox having already implemented similar blocks on third-party cookies, Google may be aligning Chrome's policies with these competitors to maintain its market position and user trust.
  • Long-term Strategy: Google might be anticipating a future where privacy is more heavily regulated and user concern is even greater. By adapting early, they can help shape the narrative and the technology used for advertising in this new landscape.

It's important to note that while third-party cookies are being phased out, this doesn't mean the end of all tracking or data collection. Google and other companies either already have or are exploring new methods that are potentially more privacy-centric but still allow for targeted advertising and analytics.

First-party vs Third-party cookies

In case you are unaware, cookies are small files of information that are saved on your browser. First-party cookies originate from the domain you are on and are used for example to remember settings and store login information. Third-party cookies are from other domains or legal entities and can be used, for example, to track website usage, conversions and retargeting across multiple domains. The third-party cookie deprecation does not affect first-party cookies.

How will this impact your digital marketing?

If you are currently running or plan to run digital marketing in the future you need to take this change very seriously especially if your campaigns use remarketing or retargeting optimisation. Additionally, if you rely on accurate analytics data via GA4 you should not ignore this change.

Over the past few years Google has developed two new products that provide a privacy centric approach to marketing tracking for a cookieless future:

  • Enhanced Conversions
    This is a feature that takes customer’s data when a user converts on your website, such as their email address, hashes it for anonymity and then sends it to Google without the use of cookies. The data can be used by Google for remarketing optimisation of Ads campaigns. As this is your own first-party data and users server-to-server communication between your website and Google it is not affected by the loss of third-party cookies.

    Google predicts that advertisers will see a conversion uplift of 10-20% after implementing Enhanced Conversions.
  • Consent Mode version 2
    This feature works in conjunction with your website’s cookie consent management application by sending information about what type of cookies your users accept or decline. Google can then adjust how, for example, GA4 and Google Ads conversion tracking functions in order to comply with your users’ privacy preferences. Again, as this is a server-to-server communication it can function either with or without users’ accepting marketing and analytics cookies.

    This benefit is important according to Google as you will preserve the ability to track conversions and use first party audiences, with 5-10% of lost conversions being recovered.

Utilizing these products will ensure that your marketing campaigns will not be negatively impacted by third-party cookie blocking.

And in fact, when properly configured by your digital agency or in-house team, both of these new services should provide a boost in campaign performance due to their ability to gather the user behavior data typically lost when users decline cookies. So potentially a win-win - improved user data privacy and marketing campaign performance.

What should you do to prepare for this change?

You should act now as time is running out. The second phase of the roll-out from Google happens on 6th March 2024 when you will no longer be able to create new remarketing audiences, and your current remarketing audiences will no longer populate, unless you have consent mode version 2 in place.

So talk to your digital marketing agency or in-house team as soon as possible and make a plan to add a compliant cookie consent management platform or ensure your current platform is compliant. Then implement both Google Enhanced Conversions and Consent Mode Version 2 via the Google gtag or Google Tag Manager.

Other platforms


In Facebook, the loss of third-party cookies can be mitigated by utilising their Conversions API. This is a cookieless server-side solution that automatically sends hashed customer data such as their name, phone number and email address back to Facebook when a user makes a purchase or fills out a lead. Facebook then matches the customer data you provided with the users that were served your ads. As this is your own first-party data being sent directly to Facebook, it is not affected by the loss of third-party cookies. 


Similarly to Google, there are also Enhanced Conversions in Bing. They work in the same way by sending your hashed customer data to Microsoft when they convert, who then match it to their users. As this is your own first-party data, it is not affected by the loss in third-party cookies. It is important to note that Microsoft is still rolling out enhanced conversions, so you will need to regularly check.


Like Facebook, LinkedIn has a conversions API. Instead of being able to implement it immediately, you will first have to apply for it via LinkedIn developer portal. The LinkedIn conversion API works by sending your hashed customer data to LinkedIn who then match it up to the users who were served your ad. As this is your own first-party data, it is not affected by the loss in third-party cookies.

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