Sell-Side Curation Explained

Sponsored by Azerion

Every couple of years, a new (or renewed) concept emerges in the ad tech space with the promise that it’s going to cure what ails modern-day advertisers and publishers. Some of these emergent concepts are little more than smoke and mirrors. Others are so foundational and logical that we wonder why it took so long for the industry to get there. 

Curation—specifically sell-side curation—falls into that latter bucket. It’s going to top a lot of the buzzword lists heading into 2025, but make no mistake: It’s not a flash in the pan. It’s a big part of how this industry of ours is going to operate going forward. 

The AdTech Explained Team developed this explainer, in partnership with Azerion, to help you better understand the role of curation in the digital advertising ecosystem, including how it works and why it is beneficial.

What is curation?

The ad tech industry loves to contort the meaning of existing words for its own purposes (cookies, anyone?). But in the case of curation, the concept has typically been used in a relatively straightforward way. Essentially, curation is all about bringing a third party in—one that neither owns nor transacts media—to select and organize media in a way that’s more useful for buyers. 

Think of sell-side curators like art curators: They’re not painting the art themselves, and they’re not buying it to hang in their own homes. They’re just there to use their knowledge to bring together a collection, from many disparate artists, that they think you will like, based on what they know about your needs and desires. 

With sell-side curation, the idea is to allow one entity, typically a data owner, to add their data to publisher-controlled inventory to provide buyers with a curated inventory pool that has some additional characteristic. For example, the inventory might represent high-net-worth individuals, or placements with high viewability, or certain creative formats. Not to be cliché, but the possibilities truly are endless in this regard. 

For the visual learners out there, it might be useful to look at this infographic: 

Based on our industry’s legacy definition of curation, there are topline parallels between curation and the function of an ad network for example — a platform that connects advertisers and publishers to facilitate the buying and selling of digital inventory. However, looking at how “curation” has evolved this year, it would be fair to suggest it has become more synonymous with the specific impact, value, and benefits of programmatic buying as it relates to moving DMP functionality to the sell-side as detailed in this infographic, retooled on modern supply technology. This shift introduces key differences that separate curation from broader definitions associated with ad networks and SPO via a DSP—something to which curation is also often compared.

So, why are we hearing so much about curation right now?

Curation isn’t a new concept in programmatic advertising. It’s just that, historically, the packaging process was happening through DSPs’ data marketplaces. Under this model, advertisers would pay to layer third-party audience data (often cookie-based) onto their campaign targeting. For a number of reasons—many of which revolve around the decline of long-standing audience signals like third-party cookies and IDFA—the buy-side process is being upended right now.

Ari Paparo has famously referred to curation as the “anti-SPO,” and for good reason. As Ari puts it:

Sell-side players, in rolling out curation offerings, are responding to buyer concerns around the declining relevance of third-party cookies, brand safety, wasted ad spend on made-for-advertising (MFA) sites, and underperforming inventory as a whole. They’re able to offer more transparency into the media advertisers are buying, and, in general, that’s letting buyers be more deliberate in their purchases. 

As a result of the shift to sell-side curation, the plumbing that underpins the programmatic ecosystem is evolving. The core relationship between the DSP and SSP remains the same, but where the data is applied and optimized has changed. Here’s an example of what this looks like in practice: 

1. A curation house like Azerion, which has a backbone of data, ships audiences to an SSP and finds matches to first-party data or universal IDs across publisher sites.

2. The SSP then packages that audience into a targetable Deal-ID.

3. The SSP sends the Deal-ID to the DSP.

In this revised, sell-side integration, the DSP doesn’t need to know which alternate ID has facilitated the audience matching, and it doesn't have to look at identifiers within the bid request as all audience matching has been pre-qualified upstream with the SSP. This enables better user matching, data addressability, faster outcomes, and greater security. 

Ultimately, SSPs and curation houses can now offer a similar service as legacy DMPs: customizable audiences, based on first-party data from publishers, blended with data from other sources. Importantly, this new approach to curation is capable of weathering the decline of third-party cookies while still enabling activation of second- and third-party audiences in a programmatic open marketplace.

What are the benefits of curation?

Sell-side curation wouldn’t be booming if there wasn’t a level of win-win-win happening. Here’s what the main players are happy about when it comes to curation:

Data owners: There are a lot of reasons for data owners to be pleased with the sell side approach to curation. With curation, data owners only need to integrate their data once, which then functions across all DSPs via Deal-IDs, simplifying deployment and expanding reach. Curation also enables data owners to set their own pricing models, whether through revenue-sharing or CPM structures, granting them better control over their revenue. Distribution becomes more selective, as data owners can limit access to specific buyers through private marketplaces (PMPs) or apply data to particular types of inventory. Additionally, this approach accommodates a broader variety of data, overcoming the typical DSP focus on user-based lists by supporting data tied to sites, placements, and other non-user-specific attributes. Finally, sell-side curation allows data owners to sell data independently of media, ensuring that they can maintain greater ownership and flexibility in how their data is used and shared.

Publishers: Sell-side curation is the ultimate weapon for publishers in the fight back against DSP-led SPO initiatives. By leveraging curation, publishers reduce the pressure to allow inventory resale by data owners. This approach also simplifies the process of onboarding new partners without requiring modifications to ads.txt. Publishers can generate additional revenue with full transparency into why their inventory is being purchased, gaining insights that support better business decisions. Curation also enables publishers to control the relative pricing of their inventory versus data.

Buyers: Finally, and most importantly, why do the people spending the money like sell-side curation? Ultimately, as far as the buyer is concerned, this approach is about enhanced quality and brand safety, a privacy-centric approach in a cookieless future, and improved efficiency and performance. By bypassing DSP-led SPO, curation gives buyers greater access to desired data segments, expanding their reach while retaining control over targeting. Implementation is simplified through Deal-IDs, and new kinds of data are available through this type of curation. Unlike programmatic guaranteed (PG) deals, curation preserves buyers’ ability to target and optimize, offering flexibility without limiting performance. Furthermore, curation reduces the need to buy from resellers.

See? Win-win-win. 

So, what are the drawbacks of curation?

With curation, it’s less about overt drawbacks than it is about a shift in how our industry operates—which can bring out the critics and naysayers with an interest in preserving “business as usual.” As Paparo notes: 

For others, curation sounds like just another layer in the programmatic supply chain—a complex chain where buyers are actively looking to remove layers right now. But, as Paparo also notes:

• Transparency: Arguably buying a deal from a curator is far more transparent that the alternative of buying the inventory from a reseller. And while buying on the open exchange using a DSP might be preferable in this regard, it also might not be feasible.

• Margin: The way the curation systems I’ve seen are built, the publisher accepts a specific pricing strategy from the curator, and is fully aware of the mark-up being taken. This is radically more transparent that previous ad network models.”

What else should marketers and publishers know about curation?

One big advantage of sell-side curation helps tackle a common concern buyers have with first-party publisher data: scale. Many publishers worry their audiences alone aren’t big enough, but by joining curated marketplaces, they can extend their reach to audiences off their sites, similar to what retail media networks do. Again: Sell-side curation is one of the only mechanisms poised to survive the demise of third-party cookies while still enabling activation of second- and third-party audiences in the programmatic open marketplace. 

That said, with the added scale and targeting quality, curated marketplaces often come at a premium. But that higher price tag also means a promise of better quality. In addition to reducing MFA clutter, curation also minimizes bid duplication, where the same inventory is offered multiple times across SSPs.

Sell-side curation also gives publishers a way to activate their first-party data in programmatic environments, something that’s been on their to-do list for years as part of long-term monetization goals. Additionally, curation boosts a publisher’s contextual targeting abilities. As privacy regulations shift targeting away from user behaviors toward content-based signals, having this added contextual targeting capability is becoming even more valuable.

What’s Azerion’s role in the curation space?

The programmatic ecosystem is growing more complex, with rising ad fraud, MFA, and a shrinking pool of cookie-based audiences leading to higher costs. Advertisers face mounting pressure to improve performance, reach, and efficiency, all while navigating an increasingly risky open web.

These challenges are exactly what Azerion's sell-side curation addresses. By sourcing safer, higher-quality open web inventory and optimizing for non-cookie-based audiences, Azerion enhances data addressability, drives incremental reach and scale, and boosts campaign performance.

Sell-side curation is a new evolution, shifting valuable data from DSPs to SSPs. Azerion integrates its technology, data, and audiences with major exchanges, making programmatic planning, buying, and activation faster, easier, and more efficient.

Azerion Inc is a full-stack digital advertising partner for agencies, brands, and publishers that offers custom audience solutions across CTV, online video, DOOH, audio, and in-game solutions. The company is at the forefront of the move to sell-side curation, helping to make programmatic planning, buying, activation, and success faster, easier, and more efficient.

Sponsored by Azerion