Curation and the new middle

For years, the big fight in programmatic was about cutting out the middle. SPO trimmed paths, first-price auctions simplified rules, DSPs connected straight to publishers. Then, around 2024, a new middle layer appeared and grew fast. It is called curation, and depending on who you ask it is either the fix for the open web's quality problem or just a new name for an old ad tech tax.

Think of a music playlist. Millions of songs exist, and most people do not want to search them all. A good playlist curator picks the best tracks for your mood. In ad tech, a curator picks impressions from thousands of sellers, adds data about the audience or context, and hands the buyer one neat "playlist" as a deal ID.

What curation actually is

A curator selects inventory from one or more SSPs, filters it for quality (viewability, invalid traffic, made-for-advertising sites, brand safety), often layers on data such as audiences or contextual signals, and packages the result into a Deal ID that the buyer activates in any DSP. Crucially, the data and the selection happen on the sell side, inside the SSP, rather than in the buyer's DSP.

1. Select supplyThe curator chooses publishers, formats and paths inside one or more SSPs.
2. FilterLow-quality, non-viewable and suspicious impressions are excluded before they are ever offered.
3. EnrichAudience segments, first-party data from brands or retailers, or contextual signals are attached on the sell side.
4. PackageEverything becomes a deal ID with a floor, sent in bid requests to the buyer's DSP.
5. Get paidThe curator's fee is usually built into the deal price or taken from the clearing price.

Who curates

Almost everyone now claims to. SSPs such as Magnite, PubMatic and Index Exchange have built curation tools and marketplaces. Microsoft, after announcing the closure of its Invest DSP, kept Microsoft Curate as a sell-side curation tool. Data companies such as audience and contextual specialists act as curators, as do agency groups, retailers with first-party data and even publishers packaging each other's inventory. On the buy side, The Trade Desk has argued buyers should do their own selection inside the DSP, using transparency data such as OpenSincera, rather than paying another intermediary.

Why curation took off in 2024–2026

• Signal scarcity. Safari and Firefox block third-party cookies, Apple's ATT limits app IDs, and privacy laws restrict what goes into the bidstream. Attaching data on the sell side avoids broadcasting it.
• Privacy Sandbox faded. Google kept third-party cookies in Chrome and in October 2025 retired most Privacy Sandbox APIs, including Topics and Protected Audience, so the industry fell back on IDs, seller-defined audiences, contextual signals and deals.
• Quality pressure. After studies exposed spend on made-for-advertising sites and invalid traffic, buyers wanted pre-filtered supply they did not have to police themselves.
• Retail and commerce data. Retailers and other data owners wanted to use their shoppers' data on the open web without handing it to every DSP.
• SSP growth. Curation gave SSPs a way to earn more from buyers instead of only cutting fees.

Where the money goes

Curation changes the money flow. In a classic open-auction trade, an advertiser's dollar pays the agency, the DSP, data and verification vendors, the SSP and finally the publisher. In a curated trade, a curator fee joins the chain, usually a take rate on the media that flows through its deals. Whether that is good depends on whether the quality gain is bigger than the fee.

1. A brand spends a dollar: A brand sets aside $1.00 for programmatic display. It hopes that dollar buys attention from real people on quality sites.
2. Agency and platform fees: The agency and the DSP each take a share for planning, buying and running the technology. The DSP’s cut is its take rate.
3. Data and verification: Audience data, Ad verification and brand-safety tools charge per thousand impressions. These can be small individually and add up together.
4. The sell side takes its cut: The SSP or exchange keeps a fee before paying the publisher. Resellers in the chain can add more hops.
5. The mystery slice: In the ISBA/PwC 2020 study, about 15% of spend could not be traced to any party: the unknown delta. Later studies found better matching data shrinks it a lot.
6. What reaches the publisher: In that study, publishers received about half of the advertiser’s spend. The rest is the ad tech tax: the price of automation, data and intermediaries.
7. And was it even a person?: Even the part that reaches a site only works if a human sees the ad. MFA sites and invalid traffic can soak up spend without reaching anyone real.

The ANA split its losses into transaction costs (the fees) and lost productivity (non-viewable, invalid and made-for-advertising impressions). Curation promises to shrink the second bucket, but it adds to the first. The honest test for any curated deal is simple: after all fees, do you pay less per real, viewable, human impression than before?

The big picture

Programmatic keeps swinging between consolidation and new layers. Header bidding broke the waterfall; first price simplified auctions; SPO cut paths; curation added a new, data-driven middle. Meanwhile, the US court's September 2026 remedies against Google will reshape how its exchange and ad server interact with Prebid and rivals. Across the US, Europe, India, Japan and Brazil, the constant questions stay the same: who touches the impression, what do they add, what do they charge, and can the buyer and the publisher both see it?