IAB Tech Lab finalizes first addressability solution

Project Rearc, an initiative within IAB’s Tech Lab, has announced the finalization of its first solution to the post-cookie addressability challenge, Seller Defined Audiences (SDA). The concept was first proposed in March 2021.

As the name suggests, this solution rests seller-side, enabling publishers or their data partners to scale first-party data in a privacy-compliant manner, aiming to “democratize the concept of audience cohorts for the open ecosystem” (from the Tech Lab release).

Publishers will be able to create and scale anonymous first-party data-based audiences across channels, including web, app and CTV. Audience members can be grouped using a standardized, but also customizable, Audience Taxonomy. Additionally, context- or content-based audiences can be created using a context taxonomy (yet to be standardized).

Among other benefits for buyers, it allows DSP machine-learning systems to optimize cohort selection through the availability of API-delivered metadata.

Why we care. It’s another addressability solution, this time rooted in the rich first-party data held by publishers. It holds out a best-of-both-worlds promise by offering audience-based and context-based addressability. And since it’s a Tech Lab initiative, it will continue to be an open and transparent work-in-progress.

The release admits “SDA makes no claims of being a silver-bullet for the industry, but should be a valuable tool in our toolbox.” A refreshing position to take because the air is full of supposed silver bullets right now.


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About The Author

KimDavis lg

Kim Davis is the Editorial Director of MarTech. Born in London, but a New Yorker for over two decades, Kim started covering enterprise software ten years ago. His experience encompasses SaaS for the enterprise, digital- ad data-driven urban planning, and applications of SaaS, digital technology, and data in the marketing space. He first wrote about marketing technology as editor of Haymarket’s The Hub, a dedicated marketing tech website, which subsequently became a channel on the established direct marketing brand DMN. Kim joined DMN proper in 2016, as a senior editor, becoming Executive Editor, then Editor-in-Chief a position he held until January 2020. Prior to working in tech journalism, Kim was Associate Editor at a New York Times hyper-local news site, The Local: East Village, and has previously worked as an editor of an academic publication, and as a music journalist. He has written hundreds of New York restaurant reviews for a personal blog, and has been an occasional guest contributor to Eater.


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