Retail media networks (RMNs) are evolving rapidly, with in-store activations taking centre stage as brands and retailers seek new ways to monetise physical spaces. At What’s In Store for Retail Media Networks 2025 presented by STRATACACHE in partnership with NRF, Daniel Knapp, Chief Economist at IAB Europe, sat down with Alexis Marcombe, CEO of Unlimitail, the retail media joint venture between Publicis and Carrefour. Their discussion revealed how Carrefour is capitalising on the in-store opportunity and why Europe’s approach to RMNs differs from the U.S.

Europe vs. the U.S.: A Different Path to In-Store Retail Media

Retail media in Europe faces a unique set of challenges compared to the U.S. market. While the U.S. benefits from large e-commerce players that drive digital retail media, Europe’s fragmented retail landscape lacks dominant online players. Instead, European retailers have historically relied on strong physical store footprints to drive business.

According to Marcombe, this distinction has led European retailers to focus on in-store retail media much earlier than their U.S. counterparts. While U.S. digital retail media is significantly larger in scale, the in-store retail media markets in both regions are nearly equal, with each generating approximately $300–400 million in media spend.

In-Store: The Last Mass Media Opportunity?

For Carrefour, the in-store opportunity is clear — reach. The retailer engages 70–75% of households every week through its 14,000 stores worldwide. As Marcombe put it, “We are mass media. One of the last [forms of] mass media.”

Despite these massive audiences, in-store retail media remains significantly undervalued. Marcombe noted a stark gap (what he called “a canyon”) between the revenue generated from online retail media and in-store retail media. While leading retailers generate up to 2% of their gross merchandise volume (GMV) from online retail media, in-store retail media currently accounts for just 0.15% of store sales. The reason? Measurement.

The Key to Unlocking In-Store RMN Growth: Data and Measurement

Marcombe emphasized that retail media is fundamentally about performance, and performance requires measurement. Many retailers struggle to track in-store activations effectively, which limits their ability to prove ROI to brands. To address this, Carrefour has invested heavily in measurement infrastructure, leveraging loyalty data as a key identifier — what Marcombe described as “the new cookie.”

By integrating loyalty data across its stores, Carrefour can offer brands clear attribution and insights into how in-store activations drive sales. This data-driven approach aligns retail media with performance marketing principles, making it more attractive to advertisers who traditionally prioritise digital channels.

The Future of In-Store Retail Media: Omnichannel and Automation

Looking ahead, Carrefour sees omnichannel strategies as the key to maximising the value of in-store RMNs. The goal is to create a seamless experience where there is no distinction between online and offline activations. According to Marcombe, “If you’re able to play omnichannel, real omnichannel, meaning there’s no frontier between your website and your stores, then you’ll win.”

Additionally, Carrefour is rapidly digitizing its stores, installing thousands of digital screens to support programmatic buying and real-time ad delivery. However, Marcombe was quick to note that digitalizing stores isn’t just about adding screens — it’s about integrating a data-driven approach that allows retailers to automate media buying, optimize campaigns, and improve customer experience without overwhelming the store environment.

The Bottom Line

As retail media continues to evolve, Carrefour’s in-store strategy highlights a key shift in how retailers and brands approach physical spaces. By prioritizing measurement, leveraging loyalty data, and embracing omnichannel strategies, Carrefour is proving that in-store retail media is not just a legacy channel — it’s a core component of the future of retail advertising.

Watch the full discussion here.

What’s Next?

 

Retail media networks are poised for significant growth, and the physical store is increasingly being recognised as the next major media channel. However, one of the biggest challenges holding back investment in in-store retail media is the lack of standardized metrics. At the What’s In Store for Retail Media Networks event during the NRF 2025 Expo, Yara Daher of IAB Europe highlighted the collaborative efforts between the European and U.S. IAB teams to establish a foundation for measuring in-store retail media effectively.

The Missing Piece: Standardization for In-Store Retail Media

Despite the growing recognition of in-store retail media’s potential — some estimates point to a $20 billion growth opportunity — many retailers and media buyers remain hesitant to invest. According to an IAB Europe survey, a third of respondents cited the lack of standardized measurement as the primary reason for underinvestment.

To address this, IAB Europe and IAB U.S. worked together to define a framework that creates a common language and standard metrics for in-store retail media. Their goal was to ensure that all industry stakeholders, from retailers to advertisers, could align on what constitutes in-store retail media and how its impact should be measured.

Defining In-Store Retail Media

One of the key outcomes of IAB’s work was a clear definition of in-store retail media. The framework stipulates that for an activation to qualify as in-store retail media, it must incorporate data in at least one of three areas:

• Planning
• Execution
• Measurement

This differentiation is critical because while in-store activations have long existed, the integration of data-driven insights ensures they align with broader retail media strategies. The IAB also reinforced that in-store retail media includes both digital and physical experiences — ranging from digital displays to traditional in-store promotions.

Establishing a Unified Measurement Approach

To create meaningful standardization, IAB built upon existing industry methodologies, including digital ad measurement frameworks and the out-of-home media guide from the Media Rating Council (MRC). Their framework categorises in-store environments into specific zones, acknowledging that audience context within a store plays a pivotal role in campaign effectiveness.

The measurement standards are designed to encompass two core areas:

• Media Metrics – Borrowing from digital advertising, the framework introduces standardized impression tracking and ad-serving methodologies tailored for the in-store environment.
• Sales Metrics – Establishing lookback windows and measurement techniques that account for in-store shopper behaviours while integrating seamlessly into the broader retail media ecosystem.

The Path Forward

Daher emphasized that while this framework is a foundational step, continued collaboration between retailers, advertisers, and technology providers will be essential to refine these standards further. With retailers across both Europe and the U.S. (including major players like Kroger, Albertsons, and Ahold Delhaize) participating in the effort, the industry is moving closer to unlocking the full potential of in-store retail media.

As the retail media landscape evolves, these standardized measurement practices will help retailers and brands confidently invest in in-store activations, bridging the gap between digital and physical retail media in a way that is transparent, measurable and scalable.

You can view the full presentation here.

What’s Next?

What’s in Store for Retail Media Networks saw Mark Williamson, who is leading Costco’s retail media efforts, join EMARKETER Principal Analyst Sarah Marzano on stage to discuss how the membership-based retailer is entering the in-store retail media space — strategically, deliberately and in a way that aligns with its core values.

Bridging the Gap Between Retail and Media

One of the biggest challenges in retail media is integrating it into existing retail structures. Williamson acknowledged the tension between traditional retail merchant teams and media teams, and how success requires shifting mindsets. “A media publishing mindset is required to win,” he noted, but added that each retailer must find its own way to adopt this approach.

For Costco, this means ensuring its retail media strategy aligns with the company’s fundamental business model. Unlike other retailers that may look to established RMNs like Amazon or Walmart for a blueprint, Williamson made it clear that Costco will chart its own course. “If it doesn’t build upon what is core to the Costco business, it will ultimately fail,” he said.

Balancing Retail Media with a Strong Private Label

A major differentiator for Costco is its robust private label brand, Kirkland Signature, which sometimes competes directly with national brands — the very advertisers that retail media networks seek to attract. Williamson acknowledged the tension but sees an opportunity to strike a balance.

“Kirkland Signature exists to reinforce the value of membership,” he explained, adding that Costco’s retail media offering must work in tandem with, rather than against, that mission. Retail media can provide national brands with a way to compete effectively within Costco’s ecosystem while ensuring that the overall shopping experience remains aligned with Costco’s brand identity.

The Power of Membership Data

One of Costco’s greatest strengths in launching a retail media network is its deep understanding of its members. Unlike traditional retailers that must rely on fragmented data, Costco’s membership model provides a wealth of first-party data on shopper behaviour.

This creates an opportunity to deliver highly personalised and relevant advertising. However, Williamson emphasised that Costco will approach data usage with caution. “The data exists, it’s there — but how do we responsibly use it in a way that strengthens our relationship with our members?” he said. The priority is maintaining trust and ensuring that advertising efforts enhance the shopping experience rather than disrupt it.

Retail Media in Costco’s Stores: The Long-Term Play

One of the hottest topics in retail media is bringing it into physical stores, but for Costco, that move won’t happen overnight. “We have a lot of work to do in order to prepare ourselves for any kind of innovation in the in-store space,” Williamson said.

With its no-frills, warehouse-style shopping experience, Costco must be careful about how and where it introduces retail media. While digital signage and app-based experiences could provide opportunities, Williamson stressed that any in-store activation must be “incredibly appropriate for the environment.”

The Late Mover Advantage

Many retailers have already launched retail media networks, but Costco is taking its time. While there are obvious challenges to being a late entrant, Williamson pointed to a key advantage: organisational patience and discipline.

Instead of rushing to market, Costco can learn from the successes and failures of others, implementing best practices while avoiding common pitfalls. The company is also launching at a time when technology is more advanced, allowing it to build a modern, scalable retail media infrastructure without the legacy tech debt that some early adopters now face.

The Future of Retail Media at Costco

As retail media networks continue to evolve, Costco is proving that a one-size-fits-all approach doesn’t work. By prioritising member value, carefully integrating media into its retail ecosystem, and taking a long-term view, Costco is setting itself up for sustainable success in this space.

Williamson summed it up best: “If Costco gave into peer pressure, we probably would have done this 10 years ago.” Instead, the company is moving forward with a strategy that stays true to its brand, ensuring that retail media is a natural extension of what makes Costco unique.

You can watch the full conversation here. 

What’s Next?