Recap d3con 2025: Retail media, measurement, and the future of data-driven marketing

Introduction

We recently had the chance to attend d3con 2025—Germany’s leading conference on data-driven advertising. As a team deeply involved in marketing measurement, ad operations, and data strategy, attending d3con was a natural fit. Though we only joined for Advertiser Day, it was absolutely worth it.

Held in a movie theater (yes—reclining seats, popcorn, and nachos included), the setting was unusual but surprisingly ideal for an event full of big ideas. Beyond the creature comforts, d3con delivered where it counts: high-caliber sessions, hands-on insights, and future-focused discussions around the direction of digital marketing. However, some presentations did lean towards being more promotional. Read on for our highlights!

What is d3con?

d3con (short for Data Driven Display Advertising Conference) is Europe’s largest conference on the future of digital advertising. Held annually in Hamburg, it brings together performance and programmatic advertisers, agencies, publishers, and technology providers to discuss trends shaping the future of digital advertising—ranging from AI and automation to privacy-first solutions, measurement innovation, and audience activation.

Retail media took center stage

One of the strongest throughlines across the day was the rapid evolution of retail media. No longer a buzzword or experiment, it’s becoming a strategic pillar—and this was clearly reflected in both the volume and quality of sessions on the topic. 

At FELD M, we can also support you with these key topics. Take a look at our marketing measurement services, and don't hesitate to book a free 30-minute call with us if you'd like to hear more about how we can support you.

Panel: “Data-driven retail media? Die Rolle von Datenanalyse und Automatisierung im Einzelhandelsmarketing”

The expert panel included Nadine Kamski from L’Oréal, Björn Wolak of dmr Advertising, Nico Winkelhaus from Payback, Christian Raveaux of Rewe, and Lena Schütze from Douglas. Each panelist provided unique insights into the future of retail media, covering topics such as data infrastructure, automation, and measurement.

Key highlights from the session:

Onsite vs. offsite media

Retail media is expanding beyond retailers’ own websites. Offsite formats—ads shown on external platforms using retailer data—are crucial for full-funnel coverage.

Measurement maturity

Panelists emphasized the importance of incrementality testing, which helps isolate the true lift driven by a campaign. Techniques like brand lift studies and controlled experiments are becoming vital as retail media competes with established channels such as TV.

Data clean rooms

Several speakers highlighted clean rooms as foundational for privacy-compliant collaboration.

What is a data clean room?

A data clean room is a secure environment where multiple parties can analyze combined data sets without exposing personally identifiable information (PII). This enables advertisers and retailers to share insights while respecting privacy regulations.

Automation and self-service

Tools enabling brands to launch and manage campaigns—such as Sponsored Product platforms and automated media buying—are becoming essential capabilities.

CTV’s emerging role

Connected TV (CTV) was mentioned as a key growth area for retail media, offering new touchpoints for audience engagement.

A culture of experimentation

There was strong agreement across the panel: success in retail media depends on building a test-and-learn culture, where experimentation and adaptability are encouraged.

Case study: Deutschland Card’s journey to commerce media

One of the most compelling case studies came from Dr. Julia Vogel and Bastian Wahl of Deutschland Card, who presented their transformation from a multi-partner loyalty program into a fully-fledged commerce media platform.

Key highlights from their session:

• Their BonScan tool enables high-quality first-party data collection across multiple retailers.
• To clean and standardize inconsistent brand naming, they developed a process using score-based large language models (LLMs) – an elegant solution to a very real data quality challenge. To enable secure collaboration with partners, they implemented a data clean room that supports privacy-safe audience sharing.
• Their current offering spans onsite and offsite advertising, backed by transparent reporting and KPI frameworks that allow partners to track and optimize performance.
• We also spoke with Dr. Vogel after the session about measurement challenges, specifically, how to select KPIs that reflect campaign effectiveness without oversimplifying success.

Modern measurement: Introducing Meridian

The four key principles behind Meridian: Innovation, Transparency, Knowledge Transfer and Realizability

Another standout session came from Eva Ries and Antonio Prada Martin of Google and TRKKN, who introduced Meridian, Google’s new open-source platform for marketing mix modeling (MMM).

Antonio opened with a sharp overview of the challenges marketers face today in measuring cross-channel effectiveness, especially in light of signal loss and growing privacy constraints. He made the case for a revival of MMM as a durable, privacy-compliant solution. You can find out more about how FELD M can support you with MMM here.

Eva followed with a walkthrough of how Meridian works, how to implement it, and how brands can start using it to guide smarter budgeting decisions.

What is marketing mix modeling (MMM)?

MMM is a statistical technique that evaluates how different marketing activities contribute to business outcomes—like sales—without requiring user-level tracking. It's especially useful in privacy-first environments or when attribution data is incomplete.

The session reinforced our belief in the importance of modern measurement techniques, and it increased our excitement to support clients in adopting tools like Meridian in their own organizations.

Final takeaways

Even with just one day at d3con 2025, we left with a renewed sense of momentum around some of the industry’s most pressing topics:

• Retail media is maturing quickly, with offsite expansion, CTV growth, and first-party data innovation at the forefront.
• Measurement is evolving fast, and clean rooms, incrementality testing, and MMM are rising to meet that challenge.
• Test-and-learn culture is non-negotiable, as brands and platforms alike push toward more agile, data-informed marketing.

For us, d3con reaffirmed a core belief: great marketing is powered by great data—but impact depends on smart execution, scalable technology, and continuous learning.

We’re already looking forward to d3con 2026!

Let’s keep the conversation going

Curious about any of the topics we’ve covered—retail media, data clean rooms, incrementality testing, or Meridian? We’d love to continue the conversation. Reach out, and let’s explore how these themes can support your strategy and growth.

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