In response to the advent of cookieless advertising, Agency 79 is exploring alternative identifiers, with particular interest in solutions such as EUID and First-id.
At 79 (Havas Media Network), explorations of alternatives to third-party cookies are ongoing. A shared roadmap has been defined for eight clients, highlighting the family of solutions based on alternative IDs. Among them, First-id, a French creation developed by former Prisma Media talents, stands out with promising results thanks to its first-party cross-domain cookies deployed across Europe.
“Our advertisers currently favor 100% deterministic solutions, anticipating uncertainty around probabilistic methods in light of browser policies,” explains Thibault Finas, Data Manager at 79. Probabilistic approaches, which rely on server data, operating systems, and especially IP addresses (under Google’s scrutiny), aim to extend reach as a complement to ongoing deterministic methods—a balance of certainty and experimentation.
Although deterministic methods derive their strength from consented data, notably encrypted emails for ID creation, adoption remains modest. The test of one such method, EUID, initiated in Europe by The Trade Desk, illustrates this:
“We experimented with EUID for Desjoyaux, which was encouraging, but the volume achieved was unfortunately limited. EUID deployment is still in its early stages, and we need broader publisher integration before relaunching our tests,” explains Thibault Finas.
The test focused on First-id’s cross-domain first-party cookie approach, chosen for its extended audience potential. Conducted during a branding campaign for PMU Live in June, targeting 25–34-year-olds over three weeks, the experiment compared two programmatic deals for in-stream activations in Prisma Media’s video inventory via DV360: one based on third-party cookies, the other on First-id.
The results speak for themselves: no notable discrepancies were observed across all KPIs, including target impression rate measured by Médiamétrie (a key metric), cost per 100% view, bid request volume from the publisher, and success rate.
During the test, 79 also examined distribution across different browsers.
Indicators were positive and consistent, as we observed increased delivery on browsers that no longer accept third-party cookies, notably Safari
highlights Camille Quiqueret
However, our experts identified two crucial areas for improvement to strengthen the solution’s robustness: deeper integration with DSPs, and wider adoption by advertisers to meet conversion measurement needs.