How Curation Is Transforming Programmatic Advertising in the Post-Cookie Era

What is Curation?

In programmatic advertising, curation refers to the process of selecting and packaging publisher inventory-often within private marketplaces (PMPs)-and enhancing it with audience data to create more valuable offerings for advertisers. Traditionally, advertisers would layer third-party audience data onto their campaigns through demand-side platforms (DSPs). However, the industry is shifting, with supply-side platforms (SSPs) now taking a leading role in curation to reduce dependence on third-party cookies.

Over the past few years, SSPs have rolled out specialized curation solutions like PubMatic Encore (2020) and Xandr Curate (2021), with platforms such as Magnite, Index Exchange, and Nexxen following suit. Even companies once firmly in the data management platform (DMP) category-like Audigent and Lotame-have pivoted toward offering curation services.

At its core, curation involves a third-party entity that does not own or directly transact media but instead selects and organizes inventory into premium packages. These curated packages might include audiences browsing certain content categories, showing specific purchase intent, or even inventory with high viewability scores.

While curation may resemble traditional ad networks (which also connect buyers and sellers), it’s rooted in modern programmatic infrastructure. By shifting more of the audience data application to the sell side, curation strengthens supply-side optimization and reduces reliance on DSP-driven targeting. This approach may prove crucial for sustaining large-scale activation of second- and third-party audiences in an open market as third-party cookies disappear.

Why is Curation Gaining Momentum?

Curation isn’t entirely new, but it’s booming now due to the decline of legacy audience signals such as third-party cookies and Apple’s IDFA. Previously, advertisers mostly applied audience data through DSPs. As the industry pivots toward first-party data strategies, SSPs and publishers offer more transparency and control over the buying process.

This shift has fueled the rise of sell-side curation, changing how data is applied and optimized while keeping the core DSP–SSP relationship intact. Enter curation houses: specialized intermediaries that connect advertisers, publishers, and third-party data providers.

Here’s how it typically works:

• A curation house matches identity graphs across these players on the sell side.
  
• It ships audience segments to the SSP.
  
• The SSP finds matches with first-party data or universal IDs across publisher sites.
  
• The SSP then packages this audience into a Deal-ID and sends it to the DSP.
  

This means the DSP doesn’t have to process user-level identifiers within bid requests-the audience has already been matched upstream. This process boosts addressability, user privacy, and operational efficiency.

As a result, SSPs and curation houses now offer many capabilities once reserved for DMPs, helping keep second- and third-party audience activation alive in a programmatic world that’s rapidly losing cookies.

The Benefits of Sell-Side Curation

Sell-side curation has taken off because it creates meaningful advantages for all stakeholders: data owners, publishers, and buyers.

For Data Owners

• Integrate data once and deploy it across all DSPs via Deal-IDs, simplifying workflows.
  
• Gain more control over monetization through flexible pricing (revenue share, CPM, etc.).
  
• Choose exactly which buyers get access via private marketplaces.
  
• Apply data not only to users but also to contextual signals like site categories or placements.
  
• Stay independent from direct media transactions.
  

For Publishers

• Extend the reach of their audiences beyond owned sites through curated deals.
  
• Better leverage their first-party data in programmatic auctions.
  
• Improve contextual targeting capabilities.
  
• Reduce dependence on DSP-driven supply path optimization (SPO).
  
• Gain clearer insights into why and how their inventory is being purchased.
  
• Maintain stronger pricing control tied to audience data.
  

For Buyers

• Access higher-quality inventory with built-in brand safety measures.
  
• Embrace privacy-centric targeting models fit for the post-cookie era.
  
• See improved efficiency and scale-some buyers report 25–40% greater reach.
  
• Reduce reliance on opaque DSP audience segments by tapping directly into curated data.
  
• Enjoy more flexible targeting compared to programmatic guaranteed (PG) deals.
  

Challenges and Considerations

Despite these benefits, sell-side curation does introduce some complexities:

• Potential DSP pushback: With more data activation happening on the sell side, DSPs might lose influence over audience strategy.
  
• An added layer in the chain: Some advertisers are trying to reduce intermediaries, and curation introduces another step.
  
• Higher costs: Curated marketplaces often come at a premium due to their enhanced targeting and scale.
  
• Data infrastructure requirements: Effectively handling audience data demands tech investments and trusted partnerships, adding operational overhead.
  

Conclusion

Sell-side curation is reshaping programmatic advertising by offering a privacy-friendly, future-proof alternative to traditional audience targeting. By moving data application to the sell side, it delivers greater transparency, efficiency, and control-helping advertisers thrive even as third-party cookies fade away.

Yes, there are challenges, from added supply chain complexity to premium costs. But the benefits of curated marketplaces-from richer data applications to improved campaign performance-are driving widespread adoption. As the industry evolves, sell-side curation is emerging as a vital bridge connecting advertisers with high-quality audiences in a secure, efficient, and scalable way.