Broadly, curation routes ad dollars toward a smaller pool of auctioned ad inventory with a unifying characteristic or set of characteristics. Curators can filter and bundle inventory based on audience or publisher attributes, type of ad unit (e.g., premium video, interactive media, high attention), contextual information, or any combination thereof.

Curation has been on the uptick for years. The Trade Desk (TTD) made waves with its Sellers and Publishers 500+ Marketplace last year. The solution, essentially a large inclusion list, narrows the open web down to a subset of websites and apps that TTD regularly vets and updates. In 2022, GroupM launched Premium Marketplace to provide clients with direct access to high-quality inventory. The trail of curation-related products dates back to before 2021, when PMP ad spending growth started outpacing that of open exchange and even programmatic direct, per our forecast.

Now, hype is mounting as sell-side ad tech capitalizes on the trend. When curation happens on the sell side of the supply chain, data providers enrich and package ad inventory before the bid request reaches the DSP. It reduces the number of distribution points for the data provider, thus minimizing technical integrations and data security weak points.

Sell-side curation can also expand reach for advertisers. Buy-side targeting can result in overserving to small audiences and bid duplication, which can raise prices. Curated marketplaces solve for those challenges by identifying and surfacing impressions from overlooked, but still valuable, inventory sources.

But sell-side curation doesn’t always complement buy-side targeting. When PMPs aren’t delivering, the first troubleshooting tactic is to confirm whether the buyer has targeting turned off. Targeting often cancels out the scale advantages of PMPs.

Read the full report, Programmatic Advertising Forecast and Ad Tech Trends H1 2025.