Eric Perrin

Eric Perrin

Data & Analytics, US

Chrome’s Challenge: Adapting to 3rd Party Cookie Deprecation

1 March 2024
5 min

Chrome’s 3rd Party Cookie Deprecation (3PCD) is already affecting business and marketing performance. In this post, we’ll uncover how this seismic shift is reshaping today’s strategies and explore ways to adapt and succeed in a post-3PC world. 

What is happening?

Google Chrome has taken a decisive step towards privacy-first browsing, which started with the deprecation of third-party cookies for 1% of its users in January 2024. Google plans to extend this to all users by the latter half of the year. This gradual phase-out marks a significant shift from traditional user tracking methods and aligns with a broader industry move towards enhancing user privacy.

Why it matters

Chrome’s third-party cookie deprecation is more than a tech shift—it’s a revolution in digital advertising, given its 65% global market share. This change impacts advertisers, publishers, and users, especially on desktop where conversion rates are higher. Google and Meta’s reliance on these cookies for detailed user profiles and targeted advertising is facing a transformative challenge.

What will the impact be?

The decline in third-party data quality will make it less complete and accurate, potentially reducing marketing efficiency and ROAS unless advertisers adjust. Making Science’s 3PC Deprecation Impact Tool predicts up to a 30% drop in advertising-attributed online conversions and a possible 9% loss in digital revenue for certain sectors. This highlights the growing importance of first-party data (1PD) over third-party data (3PD), due to cookie deprecation.

What can be done to mitigate the impact?

There are lots of options available to handle this change – in fact, too many. It is important to understand the impact on your business and prioritize the available changes based on ease of implementation and impact. We can bucket the opportunities into mitigation and activation.


We’ve compiled a few key solutions that are aimed at reducing the loss of data volume and quality by implementing tools provided by Google and collecting better data using durable, privacy-compliant solutions.

  • We can’t stress the importance of a consent management platform (CMP) rather than a DIY solution for a consent banner. CMPs integrate with Google’s technical solutions and provide template consent banners that are compliant with the latest regulatory changes in differing markets, which can become hard to manage as more and more countries and states implement their own privacy legislation.
  • GA4 implementation will provide confidence in data, become the data source of truth for the business and stay up-to-date with privacy changes, as Google has shown its commitment to keeping GA4 compliant.
  • Consent Mode V2 for all Google products and Enhanced Conversions will allow for better matching by Google whilst respecting privacy. Consent Mode is now a requirement for using advertising features within Google products, and Enhanced Conversions allow conversions to be tied to impressions and clicks better, improving the understanding of campaign performance.

We deem those as the initial essential requirements for dealing with 3PC deprecation, but there are also other measures, such as

  • Implementing server-side measurement that will further improve the robustness of the GA4 implementation and marketing pixels
  • Leveraging server-to-server APIs for key conversions to ensure 1-to-1 matching between internal databases and ad/martech. 
  • Greater understanding of users can be achieved by using a Customer Data Architecture (CDA) or a Customer Data Platform (CDP) and cleanroom analysis can help cluster users together for better-aggregated targeting.

What activation strategies can help navigate 3PC deprecation effectively?

In addressing the challenge of third-party cookie (3PC) deprecation, a myriad of strategies are available to adapt and thrive. The key is to assess the impact on your business and prioritize strategies based on their implementation feasibility and potential impact.


Focusing on activation strategies that leverage first-party data (1PD) is crucial. Here’s a breakdown of key action items:

Building and Enhancing Audiences:

  • GA4 Audiences: Utilize GA4 to create dynamic audiences based on user behavior. These audiences can then be seamlessly integrated into Ads and Google’s adtech stack, improving the precision of your targeting.
  • Customer Match: Automate the process of uploading customer lists into Ads for more accurate targeting, helping to counteract the impact of 3PC deprecation.

Leveraging Google’s Advanced Tools:

  • Smart Bidding: Implement Google’s Smart Bidding to optimize campaigns using AI, which adjusts bids in real-time for conversions or conversion value, making use of contextual signals and machine learning.
  • Consent Mode V2 and Enhanced Conversions: Ensure compliance and improve data accuracy with Consent Mode V2, now a requirement for Google product advertising features. Enhanced Conversions improve the linkage between conversions and ad interactions, offering a deeper understanding of campaign performance.

Enhancing Signal Quality:

Predictive Modeling with Gauss Smart Advertising: Beyond the scope of Google’s tools, Gauss Smart Advertising enhances your digital strategy through predictive modeling. This tool does more than just score users; it significantly enhances the signals sent to Google’s algorithms for unparalleled optimization. Such advanced techniques can sharpen your advertising efforts and lead to more targeted, impactful campaigns that elevate performance thoughtfully and effectively.


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