How the disappearance of third-party cookies is an opportunity

Antonio Mas

14 March 2024

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We’ve been preparing for the disappearance of third-party cookies for so many years that it’s hard to pinpoint when we truly began discussing this paradigm shift. From the steps taken by other browsers like Safari in 2017 or Firefox in 2019, to the successive delays experienced by Chrome, the journey to the disappearance of cookies becoming a reality has been long.

But now it’s really happening: the technology that has dominated the way users are segmented, conversions are tracked, or retargeting is done since the early days of the Internet is going to disappear definitively (although, to be precise, the change will be implemented gradually until the last quarter of the year).

Obviously, the disappearance of cookies is good news for users: less personalised tracking, more privacy, and more control over their information.

But, above all, it’s great news for Google. The market-leading search engine company (Chrome has over 64% of users) becomes the true owner of information. This gives them a much more sophisticated segmentation capability, allowing them to offer advertisers the possibility of truly targeted campaigns. At the same time, it puts other advertising platforms, especially small and medium-sized ones, in a complex situation, as they are left without the ability to offer adequately segmented inventories.

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Publishers, on the other hand, will lose part of their ability to monetise, which depends largely on the effectiveness of campaigns. There are already studies pointing out that, without cookies, user data is worth 30% less.

And what about advertisers? Undoubtedly, brands are facing a new paradigm, and although many of them are already working on that immediate future, others do not understand the great transformation that is coming: once again, the dynamism of digital marketing forces us to step out of our comfort zone. Faced with the inevitable, we can only seek opportunities and try to gain a lead on the competition. Here are some areas of work that advertisers should have on their radar.

Obsession with first-party data.

First-party data is the company’s own data that typically resides in our ERP, CRM, mailing lists, or any other database where the user has given us direct authorisation to collect them. Thanks to first-party data, brands can:

  • Conduct detailed customer segmentations based on socio demographic profiles, consumption habits, and interactions with our digital assets.
  • Activate more effective audiences on advertising platforms, increasing return on investment.
  • Personalise experiences on digital assets, improving offerings, customer satisfaction, and lifetime value.
  • Perform advanced analytics on their data.

Obviously, this implies first working to capture such data at all possible touchpoints and then integrating it into a single platform – a CDP or Customer Data Platform – that allows creating unique user profiles through a differentiating ID.

In the coming months, CDPs are going to be one of the obsessions of marketing departments, which will have to negotiate with their IT and legal colleagues to achieve rapid implementation, given their strategic nature.

In summary, brands must work in two directions:

  • Capture their own data. Every interaction with the consumer is an opportunity for them to authorise us to save and use their data. Once consent is given, we must ensure that we are adequately monitoring their activity at each touchpoint.
  • Adopt a CDP that allows them to understand the identity of each customer and have all the information necessary for marketing and sales purposes.

The rebirth of contextual advertising.

Contextual advertising is advertising that seeks to match user interests with the promoted product, selecting placements based on their content and relevance to the advertiser.

Although not new – contextual advertising has been with us for many years – it is true that, in its beginnings, its effectiveness was often questioned (we will never forget those airplane ticket ads on news about air accidents or the promotion of knives in murder news stories). But things have changed, and now the signals taken into account are not exclusively related to content.

Some platforms – including one of the pioneers, Seedtag – apply Artificial Intelligence and natural language processing to the placement decision process, considering relevant points such as brand safety, possible references to the competition, the tone and intent of the content, and even the brand’s communication objectives to decide on the correct placements. This is in addition to AI vision, which recognises the contents of images and videos to further adjust space relevance.

Platforms allow selection from hundreds of categories and rules that help further adjust the appropriate connection between space and product. If we add dynamic creatives to further improve integration, contextual advertising has reached a level of effectiveness that earns it a place on the first page of your marketing plans.

CMP, Consent mode, and why you should worry about the cookie acceptance rate.

Let’s start by detailing how a CMP works. A Consent Management Platform is a tool that collects and manages, easily and accessibly, user consent options for the use of cookies and tracking pixels, so that they can adjust their privacy options whenever they want. Among its advantages is the possibility of having a unified record between websites, generating process statistics, creating audit logs to demonstrate compliance with privacy regulations, measuring acceptance rates, conducting A/B tests, offering multi-language management… You’ve probably come across some of the best-known ones, like Cookiebot.

Consent Mode is Google’s tool with which CMPs connect to transfer user consents to various Google products, including Google Analytics 4 (GA4) and Google Ads, and which will need to be used from now on – March 2024 – to be able to activate audience segmentation functions and campaign performance measurement.

The key to Consent Mode is that it allows modeled conversions, that is, it can estimate the number of conversions generated by users even if they have not given their consent, retrieving data from over half of ad clicks. And, remember, it can only be activated through a cookie banner that natively integrates with Google via API.

In short, in this new paradigm, activating Consent Mode will be essential to obtain maximum information about conversions, whether direct or modeled, and calculate ROI.

In any case, our goal should always be to optimise the cookie acceptance conversion rate, to try to reduce as much as possible the number of directly untracked conversions and to make our audiences as precise as possible. The cookie banner becomes a CRO object.

Keep an eye on Google’s solutions.

In this context, Google is aware of the need to propose alternative solutions that allow generating appropriately segmented advertising while respecting users’ privacy. And that is precisely its proposal with Privacy Sandbox, a set of solutions that seek to balance privacy with advertising effectiveness and behavior tracking. Here, we highlight the most relevant ones.

1. Topics.

Google has built a series of hierarchical categories (for example, vehicles / cars / off-road) with which, depending on the sites visited, it classifies our browser, assigning it three topics that are updated weekly. For example, this week it could be yoga, investment, and hotels, and the next it could be cars, cooking, and tourism.

Currently, the number of categories is around 500, but Google expects it to soon surpass four digits; enough to be effective, but not so much as to jeopardise user privacy (in addition, topics can be modified or deleted by the user in Chrome settings and will not be accessible through the API in incognito mode).

So, every time a publisher receives a visit from a user, it will read the three topics assigned to them that week and the process of auctioning off advertisers interested in that profile will be established.

But does it work? Google has been publishing comparative results between Topics and campaigns with third-party cookies, claiming that the decrease in effectiveness is not significant. The credibility of these results, being both judge and party, is determined by the reader themselves.

2. Protected audience.

Privacy Sandbox’s retargeting solution addresses privacy concerns by conducting auctions within the browser itself, without exchanging user information during the process. In this solution, the advertiser and their provider (DSP) define interest groups for the campaign. Users are assigned to these groups after demonstrating a predefined series of behaviors, such as visiting a product or adding it to the cart.

Thus, the browser will record the name of the interest group, the group owner, user signals, and information that will allow the browser to enter the auction. The DSP only receives the group it belongs to – which must have at least 50 users to guarantee anonymity – but since the IDs of the products, categories, or pages with which the user has interacted are stored in the browser, the most relevant banner can be displayed when winning the auction.

3. Custom audiences in GA4.

This functionality allows the creation of user segments based on their behavior, whether segmenting by dimensions, metrics, or events. Thus, it gives us the possibility to group users by criteria such as visiting a page of a product category or adding an item to the shopping cart.

By connecting the GA4 account with Ads, the audiences are added to the Ads library and, therefore, can be used in campaigns. Let’s remember that, in addition, we can combine audiences with exclusion groups for greater precision; for example, users who have added to the cart, excluding those who have completed the purchase.

Users who are part of a custom audience can remain in it for up to 18 months from their last inclusion, facilitating long-term planning and the building of lasting relationships with customers.


The cookieless world is already a reality, and there is no turning back. This is the playing field we will compete in from now on. Brands must change their mindset as soon as possible, learn the new rules of the game, familiarise themselves with the tools, and seek differentiating elements over their competitors, building the best customer experiences under a new privacy paradigm.