August 9, 2025
2 min read
Seller-defined audiences (SDA) represent a privacy-conscious targeting framework pioneered by the IAB Tech Lab, designed to enable publishers to segment and share audience data while preserving user anonymity and eliminating dependency on third-party cookies. The core mechanism involves publisher-driven user segmentation, where publishers categorize users into audience groups based on context, behavior, or first-party data—such as "sports enthusiasts"—without exposing personally identifiable information.
The SDA framework mandates adherence to a standardized taxonomy and labeling system established by IAB, ensuring uniformity and interoperability of audience segments across different platforms. This is crucial for maintaining consistency in how audience data is defined and interpreted in the advertising ecosystem.
Advertisers engage with these segments through ad exchange bidding, participating in auctions where they bid on audience segments rather than individual user identities. This approach effectively balances targeted advertising needs with stringent privacy requirements, reducing risks associated with data leakage and enhancing user trust.
Key findings from preliminary implementations and industry reports highlight the following:
Limitations observed include potential variability in segment quality depending on publisher data richness and the need for ongoing refinement of the taxonomy to capture evolving audience behaviors.
In summary, seller-defined audiences offer a pragmatic balance between personalized advertising and privacy preservation by enabling publishers to maintain control over audience definitions within a standardized, privacy-first framework.
