London Calling: Do You Really Know Your Customer?
Why I'm hosting a roundtable on Single Customer View at Martech World Forum — and why you should join us
Last week, I was finetuning the Zingg website, when something caught my eye. We have a quote on Fortnum & Mason’s journey from fragmented customer records to a unified view with Zingg:
"For the first time, we're able to understand how customers are shopping with us—online, in-store, over the phone, or in restaurants. We never had that before."
That sentence got me thinking: in an era where we can track a customer's digital breadcrumbs across every touchpoint, why do so many brands still struggle with the simple question: "Do you really know your customer?"
The Identity Resolution Promise That Keeps Getting Broken
Most of us have watched the same promises get made over and over again. First, it was Master Data Management (MDM) systems that would create "one golden record." Then identity services like LiveRamp promised to connect everyone's messy data through their identity graph. Then for the last few years, Customer Data Platforms (CDPs) became our solution to the elusive single customer view.
But here's what I keep seeing: enterprises continue to struggle with messy and fragmented data. Multi-year MDM implementations that are still not very useful. The MDM system could tell you the exact lineage of how John Smith's email address made it through seven data transformation steps, but it couldn't figure out that J. Smith from the mobile app was the same person. The system was simply not ready for the messy reality of how customer data actually behaves.
The same pattern plays out with identity services. A different promise: "Don't worry about cleaning your own house — we'll connect everyone's messy data." Unfortunately, identity services operate as closed systems where you can't see or validate their matching logic. When they say
Customer A matches Customer B, you're essentially trusting a proprietary algorithm without transparency. This becomes problematic when you need to adjust matching to your specific business context, explain results to stakeholders and debug why certain matches seem incorrect. Add to that the privacy risk of sending trusted data to a third party. Designed around fixed data models (email, phone, cookie IDs, etc.), it is tough to resolve on more complex or domain-specific attributes (like healthcare patient IDs, loyalty card numbers, or industry-specific identifiers).
CDPs were supposed to fix everything by democratizing customer data for marketers. The reality? Most became expensive data silos with pretty dashboards, lots of data movement yet the hard work of actually resolving who is who got pushed to the background.
What Actually Works
This is why I'm excited about what the team at Fortnum & Mason have built. Starting with data scattered across restaurant bookings, email sign-ups, online orders, and in-store transactions, they built a composable CDP using Zingg for entity resolution on Databricks.
The transformation wasn't about technology for technology's sake.
"We are able to start turning that into insights and use it to personalize experiences online. We are going to start doing this in store and in our restaurants as well. Being able to connect all of these different customer experiences together is really important for us."
What made their approach different? They treated entity resolution as a first-class capability, not an afterthought. They started with Zingg's open source version to build confidence, understood how the matching worked, then moved to the enterprise version. The entire journey from proof of concept to production took just 2-3 months. For the first time, they can understand how customers shop across all channels. Suddenly, “one customer” meant the same thing everywhere — and the results have been transformational, not just for analytics, but for personalization and customer experience.
Or look at the Orthodox Union, a non-profit serving millions globally. They struggled with donor and member records scattered across legacy systems, event platforms, and CRM databases. Without a reliable way to unify identities, their engagement strategies risked missing context and duplicating outreach. By resolving identities natively in their Snowflake data warehouse, they were able to create a consistent single view of donors and members, while respecting privacy and compliance requirements central to their mission. For them, identity resolution wasn’t just a data challenge — it was a way to deepen community trust.
These are two very different organizations, but the pattern is the same: composability delivers agility, while identity delivers coherence. Without both, the vision of modern customer experience falls short.
The Composable CDP Revolution
Fortnum & Mason's and Orthodox Union’s approach reflects a broader trend that's reshaping the market. Composable CDPs sit on top of existing data clouds to preserve the customer 360 and activate real-time data across channel tools. Instead of moving data around, they work where the data lives. They are private by design. They leverage existing investments in governance and observability. They scale as you grow.
But here’s the hard truth: Composable architectures give you flexibility — but only if the components are stitched together with a stable, reliable, and explainable identity layer. You can have the most elegant semantic layer, real-time pipelines, and activation tools, but if “Acme Corp” and “ACME Inc.” are treated as two different customers, your insights fracture. If one table says “Tim Chen” and another says “T. Chen,” your campaigns lose relevance. If customer data is duplicated at ingestion, those cracks echo through every model, dashboard, and recommendation.
And here’s the other piece we don’t talk about enough: owning your identity layer means owning your customer understanding. Instead of shipping your most sensitive data out to a black-box vendor, you resolve identities where your data already lives — in your own warehouse or lake. That means:
Data ownership: You stay in control of your customer data, critical in a world of tightening privacy regulations.
Schema flexibility: As your business evolves — new channels, attributes, and data types — your identity system evolves with it, instead of breaking because it was designed for someone else’s schema.
Privacy and compliance: By resolving identities within your existing data governance framework, you respect customer consent and meet regulatory requirements without creating extra data copies.
Stack leverage: You’re not rebuilding infrastructure. You’re making your existing investments in warehouses, lakes, and analytics more powerful by adding the missing link: identity.
Why I'm Hosting This Roundtable
This brings me to London. On 9th September, I'll be at the Martech World Forum hosting a roundtable titled "Do You Really Know Your Customer?" — and it will be lovely to meet you if you are there!
Here's what we'll cover:
The Identity Crisis in Marketing Why traditional approaches to customer identity keep failing, and how agentic AI makes the problem more urgent than ever.
Building Composable CDPs That Actually Work Moving beyond tool marketing to understand what composable really means, when it makes sense, and how to implement it successfully.
The Zingg Approach to Entity Resolution How modern ML-based entity resolution differs from traditional MDM, why transparency matters, and how to get started with open source tools.
Real Customer Stories on fragmented data to unified customer understanding, including the practical challenges and business outcomes. The folks from Fortnum & Mason will join us to share their real-world experience, the challenges they overcame, and the business impact they've achieved.
The roundtable format means we can go deep, ask tough questions, and learn from each other's experiences. Whether you're just starting your customer identity journey or you've been through multiple implementations, there is value in understanding what's working now and what's coming next.
Join Us in London
I have a limited number of VIP passes available for the Martech World Forum. If you're a data or marketing leader in London, I'd love to share the passes and have you join the conversation in person. Because at the end of the day, the real question isn’t just “do you know your customer?” — it’s whether your systems know them too.
Not just their demographic data or their transaction history, but their actual journey across all your touchpoints? Can you recognize them when they call customer service after browsing your website? Do you know that the person who signed up for your newsletter is the same one who made a purchase in your store?
If you can't answer these questions confidently, you're not alone. But you also can't afford to stay in that position much longer.
The companies that figure this out — the ones that truly know their customers — are going to have an unfair advantage in the age of AI-driven experiences. They'll deliver more relevant products, more timely services, and more personal interactions. They'll waste less money on duplicate processes and misguided campaigns.
Most importantly, they'll build the kind of customer relationships that survive economic downturns, competitive pressures, and technology transitions.
And if you can't make it to London but have war stories about identity resolution initiatives (successful or otherwise), I'd love to hear them. This isn't really about technology — it's about understanding the humans behind the data. And that, I've learned over the years, is both the hardest and most rewarding part of what we do.
Want to learn more about entity resolution and composable CDPs? Check out Zingg's open source project or read about how we're helping companies like Fortnum & Mason build better customer understanding.