The Era of the Sell-Side Platform: Making Sense of the New Ad Tech Landscape

Sponsored by OpenX

Once upon a time, there was the buy side, and there was the sell side. Buyers bought, sellers sold. The digital advertising ecosystem was simple.

Well, maybe not. There hasn’t actually been a moment in time where it would have been appropriate to characterize the digital ad industry, and the tech ecosystem that supports it, as simple. But once upon a time, everyone felt pretty comfortable that they knew who did what. 

All the forces that have been propelling digital advertising into a cleaner, more transparent, and more sustainable future have driven the ascendance of SSPs, whose relationships with publishers provide the unique ability to provide tools for both transparency and control. In a world ruled by privacy initiatives, loss of legacy identifiers, and supply path optimization, SSPs have become a preferred partner of publishers and advertisers alike. They’re taking the lead on data, identity, and curation, and they’re changing the ad tech playing field in the process. 

To understand why sell-side platforms have (seemingly suddenly) become the digital ad industry’s hottest power players, we spoke with Matt Sattel, chief revenue officer at OpenX. Here’s what advertisers need to know about the shifting balance of power in our industry. 

OK, let’s start with the basics: Why are SSPs getting so much more ink in the trade press these days when compared to other platforms? 

The most straightforward answer is the role of the SSP is evolving, and that’s attracting attention. Differentiated SSPs like OpenX are no longer simply a commodity but rather an important strategic solution for brands and agencies. This makes sense when we consider the direction the ecosystem is moving: With a growing percentage of media buys being transacted programmatically, there is also increased scrutiny on programmatic performance and data privacy.

Given how closely SSPs sit to inventory, brands and agencies are finding that SSPs are effective partners not only in managing brand safety or viewability standards but also in ensuring performance metrics are achieved, privacy standards are upheld, and transparency into exactly what they're buying is being provided. That’s why direct access to supply is more important than ever – and why you’re seeing more about SSPs in the trades. We’ve seen where this industry is headed, and we’ve been evolving our capabilities to deliver on what buyers are asking for most – control, transparency, and performance. 

Curation is the buzziest topic in ad tech right now, and SSPs have really taken control in this realm in recent years. Let’s look ahead: What are you most excited for in the next phase of curation?

Curation in programmatic advertising isn’t new – but it has evolved recently, and that’s leading to a lot of different definitions within the industry. Curation began with site lists and other inventory-led curation solutions. This type of inventory curation still happens today, and it’s an important tool that helps many of our brand and agency partners meet standard needs like securing brand-safe inventory at an efficient cost.

Innovative SSPs dug into programmatic and built data-targeting capabilities. Data-driven curation now allows agencies and brands to leverage audience, behavioral, or retail data to efficiently reach qualified consumers at scale and enhance the effectiveness of their working media — all through a deal ID. Additionally, SSPs like OpenX are leveraging data signals to enable scaled contextual targeting across environments like CTV by normalizing the content object signals we see, enabling buyers to target scalable content through deals. 

The next wave of curation will use AI to deliver better outcomes by identifying higher-performing media placements. For example, we are currently beta-testing a solution that leverages machine learning and deep neural networks to identify and package the inventory that performs best against an advertiser’s chosen goal. This is particularly valuable for agency and brand verticals that have high customer acquisition costs, such as auto, pharma, and personal tech, as buyers often struggle to identify their audiences at scale in environments that drive campaign performance. 

The ad tech landscape is as cluttered as ever. How are brands making decisions about their partners? What role do marketplace guides or reports play?

Programmatic is both complicated and nuanced. It’s important to seek out industry experts and entities that understand the landscape and can therefore advise with authority rather than guess. 

It’s also important to consider the motives behind for-profit reports. When a recent SSP report came out — one that, let’s say, needed a life jacket — it ranked three of the four non-participating companies at the very bottom of the report. Further, the report had glaring errors like failing to understand which SSPs actually had an ad server and which did not. Whether the research company actually has a grasp on the industry they’re evaluating is the most important consideration to keep in mind in order to avoid making decisions based on incomplete or inaccurate rankings.

You’ve talked a lot about OpenX acting as a trusted advisor to its partners. What are you thinking about in 2025?

One of the things we’re thinking about is how to help our brand and agency partners protect their media investments. We believe that privacy will play a pivotal role in how media is sold, bought, and measured. Today we’re tracking new global and state regulations, like Australia's Privacy and Other Legislation Amendment Bill 2024 and the Maryland Online Data Privacy Act (MODPA). Varied global and regional regulations will change brand and agency needs. They are going to need to ensure more direct paths to inventory to prevent data leakage, and they are going to need to rely on programmatic partners who deeply understand the downstream effects of regulation. Therefore, partnering with platforms who are building innovative solutions that continue to drive performance while protecting their media buys and data assets will be a priority.

All of these privacy developments will have a profound impact on how the ad tech ecosystem functions, and it’s our job to invest in building privacy-forward tools that help our partners protect their businesses and grow their brands.

About OpenX

OpenX is an independent omni-channel supply-side platform (SSP) and a global leader in supply-side curation, transparency, and sustainability. Through its 100% cloud-based tech stack, OpenX powers advertising across CTV, app, mobile web, and desktop, enabling publishers to deliver marketers with improved performance and dynamic future-proofed solutions. With a 17-year track record of programmatic innovation, OpenX is a direct and trusted partner of the world’s largest publishers, working with more than 130,000 premium publisher domains and over 100,000 advertisers. As the market leader in sustainability, OpenX was the first adtech company to be certified as CarbonNeutral™ and third-party verified for achieving its SBTi Net-Zero targets. Learn more at www.openx.com.Ad