Who Replaces Switzerland? Mathieu Roche on Rebuilding the Identity Commons

<p>For years, LiveRamp played the role of “Switzerland” in digital advertising: a neutral identity layer connecting brands, agencies, publishers, platforms, data providers, and measurement partners. But with Publicis moving to acquire LiveRamp, can infrastructure owned by one of the world’s largest agency groups still credibly claim neutrality?</p><p>In this episode of <strong>Signal &amp; Noise</strong>, Rio Longacre and Brett House sit down with <strong>Mathieu Roche, Co-founder and CEO of ID5</strong>, to explore what happens when one of advertising’s most important shared rails suddenly has an owner with a very different strategic position.</p><p>Mathieu argues that the industry now has a genuine reason to build alternatives—but replacing <strong>RampID is not the same thing as replacing LiveRamp</strong>. LiveRamp’s position was built through identity resolution, onboarding, publisher integrations, data collaboration, activation, measurement, and years of network effects. Recreating that requires more than another identifier. It may require an entirely new coalition of independent companies. </p><p>The conversation gets into what that new identity commons could actually look like. Mathieu explains why identity should function more like a common <strong>currency or language</strong> between buyers and sellers—open, interoperable, and usable across platforms rather than controlled by either side. He also explains why identity is just as critical for <strong>measurement</strong> as targeting: if advertisers cannot connect exposure to outcomes across devices and environments, they cannot prove performance or optimize investment. </p><p>Rio, Brett, and Mathieu also dig into ID5’s acquisition of <strong>TrueData</strong>, which Mathieu describes as a kind of “Rosetta Stone” connecting different identifiers, devices, users, households, and offline data into the ID5 ecosystem. The discussion explores deterministic versus probabilistic identity, why conventional “match rate” metrics can be misleading, and why the real question is whether an identifier can actually be found and activated against in the wild. </p><p>They also examine the publisher side of the equation: how identity can increase bid density and monetization, how ID5 works alongside companies such as Optable and Permutive, and why publishers need deeper knowledge of their audiences if they want to regain leverage from the buy side.</p><p>Finally, the conversation turns to <strong>agentic trading,