What after third-party cookies: best alternatives listed

Data cleanrooms, cookie identifiers, zero-party data, the Privacy Sandbox, ... We are being bombarded with alternatives to third-party cookies. Specialists Pieter Jadoul (AdSomeNoise) and Niels Waem (Deloitte Digital) provide light in the darkness and set Belgian advertisers on their way.

What are third-party cookies?

Third-party cookies are tracking files that third parties, such as ad networks and data analytics companies, place on websites to track user behavior across multiple sites. These cookies help advertisers and marketers collect data on interests, personalize ads and measure campaign results.

What about phasing out third-party cookies?

Numerous Web browsers - think Firefox, Microsoft Edge and Safari - had already decided to say goodbye to third-party cookies a long time ago, but market leader Google Chrome dragged its feet for a long time. It finally landed on an incremental phase-out that was supposed to result in a final ban by the end of 2024. Had to, because last summer came word that Chrome was not giving up third-party cookies completely after all.

A striking change in direction, which Niels Waem, Senior Digital Marketing Consultant at Deloitte Digital, said is due to the major impact of the phase-out on the company itself. “Google's main product is advertising and it needs those third-party cookies to do advertising. That's why it's now shifting its focus to browser privacy.”

In the meantime, many did actively pursue alternatives. Work for nothing? “Not at all, because people today deal with cookies much more consciously. The cookie acceptance rate is very low.” Media Director at AdSomeNoise Pieter Jadoul also knows this. “Consumers no longer allow their behavior to be captured by just about anyone. Emerce just revealed that already four in ten Dutch people say 'no' to cookies. Even on websites that make it difficult to refuse them, 27% still actively seek them out.”

Pieter therefore advises advertisers not to view these evolutions purely through technological glasses. “It is mainly the consumer reality that is changing.” And that is a story of challenges, but much more of opportunities, both experts judge.

What alternatives to third-party cookies exist?

The most appropriate alternatives to third-party cookies, in short, is the message. But what exactly are they? “Relevant advertising can be done in multiple ways,” says Pieter, ”and there is no one size fits all solution. What is the best approach differs from advertiser to advertiser and from target audience to target audience.” Niels also stresses that first and foremost you need to know what the objectives are. He distinguishes two broad categories. “Third-party cookies had a dual use: beforehand you used them to optimize campaigns, afterwards to analyze them. There are good alternatives for both phases today.”

LEVERAGING DATA FOR CAMPAIGNS

DATA COLLECTION

For advertisers, it is more necessary than ever to develop solid CRM systems or customer data platforms. “These can include both first-party data and zero-party data,” Niels points out. “They allow you to aggregate all data points in a structured way and perform valuable segmentation based on that.”

First-party data

First-party data are data about consumers that a brand or publisher collects directly through its own channels. Think newsletter subscriptions and website interactions captured through first-party cookies, all data that are thus ideally captured in a customized customer data platform.

Like Niels, Pieter considers first-party data anno 2025 an essential tool, but he adds a few caveats. “Collecting data is a good first step, but then you have to use it in your campaigns.” Logical but challenging, although data cleanrooms - about which more below - can facilitate that process. “In addition, it can take quite a long time before the scale is large enough to effectively use the data, especially in a small country like Belgium.”

Zero-party data

Zero-party data is data that consumers voluntarily and explicitly share with a brand or publisher. For example, customers can participate in contests or surveys and share their preferences in exchange for personalized recommendations. Data that can be a very useful complement to first-party data, precisely because it indicates very precisely where a person's interests lie.

DATA ANONYMIZATION AND PROCESSING

Data cleanrooms

A data cleanroom is a secure environment where multiple parties (such as advertisers and publishers) can aggregate and analyze their data without sharing identifiable user data with each other. In other words, it is a tool for anonymizing data to be used to send the right ads to the right audiences at the right time.

“Data cleanrooms make it possible to bridge the gap between first-party data and third-party data without sacrificing privacy,” Pieter explains. Advertising thus becomes just a little more complex, although that is not necessarily a disadvantage. “Brands used to just do whatever, now they think critically about each step and align the whole of their organization with that process. That often benefits the results.”

Cookieless identifiers

Pooling data anonymously to create that much-needed scale is also what so-called identifiers do. There are many variations, but the bottom line in each case is that information about an Internet user's behavior can be exchanged in an encrypted way (via a neutral third party). At the same time, identifiers enable anonymized one-to-one targeting in a sense.

However, this tool is not blissful. Pieter: “Publishers will still have to take steps in terms of cooperation in order to obtain sufficiently large and interesting volumes for advertisers.”

Google Privacy Sandbox?

Under the broader umbrella of cookieless identifiers, we may also place the principles of cohort-based targeting. This involves grouping users into anonymous segments called cohorts. Perhaps the best-known example is Google's Privacy Sandbox, but in parallel with its change of course around third-party cookies, the tech giant is letting that initiative die a quiet death.

“At the platform level, we are actually taking a step back now,” notes Pieter. “Where the big platforms facilitated mutual data exchange for a long time, we are now returning to walled gardens. For advertisers, this means making choices again: can we upload our data on Facebook and TikTok or do the values and norms of these platforms not match the expectations of our consumers?”

CAN IT BE OTHERWISE?

Contextual advertising

The alternatives cited stick heavily to the data story and to the explicit registration of interests. Yet it is also possible without data. Pieter: “That too is a challenge of our time: checking whether data have added value and whether there is another way.” Through contextual advertising, for example. Internet users are shown relevant - and therefore effective - ads based on the content and context, such as advertising for an airline next to an article on travel destinations or a supermarket offer above a recipe.

MEASURE CAMPAIGNS

When it comes to the measurability of marketing campaigns, first-party data again logically play a crucial role. But just as simply collecting some data is not enough to run relevant campaigns, there is still a big gap between capturing data and distilling useful insights from that data.

AGGREGATE DATA

Marketing Mix Modelling

The holy grail in this, according to Niels, listens to the name MMM: Marketing Mix Modeling. “That's not new, but for me it's the next big thing to invest in. After all, it's a methodology that not only helps you directly aggregate data from different data sources, but also includes analytical techniques.” All the major technology players are betting on it today.

“Such a model provides a solid answer to the most important question for a CMO: how can I achieve better results with less budget? More than that: the insights derived from MMM are even more valuable than what brands can learn from cookies.” Moreover, in AI times, functionalities are ever expanding. “In particular, predictions - predictive analytics - are getting better and better.”

Server-side tracking

Another alternative, closely related to the identifiers discussed, is server-side tracking. This is a method in which user data is collected not in the browser (client-side) but on the Web site server. That data can then be passed anonymously to analytics platforms.

CAN IT BE OTHERWISE?

Classic market research

Marketing Mix Modeling does have a downside, we learn from Pieter. “It is an excellent way to analyze data on a large scale, but they remain models behind which certain decisions are made and, in a sense, a constructed reality emerges from them.” He therefore advocates combining it with ... market research. “Because we have been on the drip of data for the past decades, we have somewhat lost sight of that classic marketing technique. However, once talking to the target group can provide deeper understanding more than ever.”

Towards 2030: what does the future hold?

Five years is a long time in a technological context, but we'll let the experts look ahead to 2030. Where will we stand with this story? "The direction seems clear," says Pieter about the coming years. "I predict a period of trial and error, an exciting time in which we will test many things and from which we will learn a lot, both about technology and about the consumer. That is also where the great opportunity lies: the winners in five years will be the brands that have embraced their customers again."

Niels, in turn, expects that the evolution towards MMM will continue. “We are moving towards an integrated solution, with only first-party data, and towards advanced APIs that will take the measurability of our websites to a higher level. AI will gain a lot of ground in the field of analytics and data enrichment. Who knows, we might not even need first-party data anymore and everything will soon be based on AI…” In the meantime, with all the geopolitical turmoil in mind, it would do no harm for advertisers to take a critical look at their entire toolbox, Pieter concludes.

“There are many European and even Belgian applications that deliver at least as good results as their large American counterparts. It is interesting to take a look at that too, especially now that third-party cookies are disappearing and consumers are very concerned about their privacy. Trust is crucial and a strong local ecosystem can help with that.” On 6 May, third-party cookies and their alternatives will be the central topic of the IAB Belgium Afterwork.