Data & identity · also called SDA
Seller-defined audiences
Seller-defined audiences (SDA) is an IAB Tech Lab specification that lets publishers label ad requests with standardised audience segment IDs from their own data, without passing personal identifiers to buyers.
Publishers know a lot about their readers from first-party behaviour: what sections they read, what they searched on-site, whether they are subscribers. SDA gives them a privacy-friendlier way to share that knowledge. Instead of sending a user ID that buyers can track, the publisher attaches segment codes from the IAB Tech Lab Audience Taxonomy, for example "interest: personal finance", to the bid request.
The standard was released in 2022 as part of IAB Tech Lab's work on addressability. Publishers can also disclose how segments were built using the Data Transparency Standard, so buyers understand the data's quality. Because the data stays with the publisher and no cross-site ID is created, SDA is intended to be more privacy-preserving than cookie-based third-party data.
Adoption has been gradual. Buyers must trust each publisher's segmentation and cannot use SDA for cross-site frequency capping or retargeting. It works best alongside contextual targeting and first-party data deals, especially in environments without third-party cookies.
Think of it like this
SDA is like a magazine telling advertisers "our readers are keen gardeners" without handing over the subscriber list.
An example
A French news publisher tags requests from readers of its personal finance section with an Audience Taxonomy segment code; a bank's DSP targets that code across 30 publishers using the same taxonomy.
Related terms
Audience segment
An audience segment is a group of people or devices defined by shared characteristics, such as demographics, interests, purchase behaviour or intent, used to target or measure advertising.
First-party data
First-party data is information a company collects directly from its own customers or audience, such as purchases, sign-ups, app use and site behaviour, through its own channels.
Contextual targeting
Contextual targeting places ads based on the content being viewed, such as the topic, keywords or sentiment of a page, video or app, rather than on data about the individual viewer.
Cookieless advertising
Cookieless advertising means targeting and measuring ads without third-party cookies, using approaches like first-party data, contextual targeting, alternative IDs, clean rooms and modelled measurement.
Bid request
A bid request is the message an SSP or exchange sends to potential buyers describing an available ad impression, inviting them to bid on it in a real-time auction.
Sources: IAB Tech Lab Audience Taxonomy, IAB Tech Lab OpenRTB