The history of the open Internet has always been filled with co-petition (or frenemies, if you’d like) organizations and frameworks that work together in some regard and compete in others. Consider it a digital cold war.
Now, a relatively new (and not so cold) war is breaking out between demand-side platforms (DSPs) and supply-side platforms (SSPs), specifically over one of the industry’s most valuable resources, data signals. Both are vying for the publishers’ attention by claiming they are worthy of their precious data signals that will continue to power the future of advertising.
The catalyst of this cold war: the continuous decline of third-party cookies and fragmented user identity and behavior. Even with Google’s decision to keep third-party cookies without the user opt-out, almost half of US browsers do not rely on third-party cookies. The combination of the industry’s multi-year quest to hedge its reliance on cookies with alternative identity solutions and the more recent advent of AI-based segmentation has created an ultra-competitive market where demand and supply are vying to control and monetize user and publisher data.
To win the war, SSPs and DSPs need to persuade publishers: which can best leverage the most valuable signals—identity, intent, engagement, and bid dynamics —for maximizing publisher revenue and advertiser performance?
In this article, we’ll outline the strengths and weaknesses of each side and the effect on the overall advertising ecosystem..
The DSP Argument: Control Drives Better Outcomes
DSPs, traditionally the central intelligence layer for advertisers, argue that signal ownership belongs on the buy-side. Their case rests on three main claims:
Advertisers Fund the Ecosystem: In the simplest terms, advertisers pay for impressions and should get maximum transparency into ad performance and in turn, reward the supply that delivers results. DSPs latest ask is to access raw publisher signals to optimize bids, reduce inefficiencies, and reach users with higher precision.
Better Cross-Publisher Decisioning: DSPs argue they have a macro-level view of users across multiple publishers, allowing them to create comprehensive audience profiles and maximize audience signals. Centralizing identity and engagement signals and implementing AI-driven optimization would help increase return on ad spend (ROAS).
Signal Transparency: DSPs claim that the SSPs’ data controls limit bid efficiency by forcing advertisers to make decisions with incomplete information. This could lead to advertisers missing out on peak traffic opportunities and paying more for lower-quality impressions.
DSPs aren’t just making the case to advertisers; they also claim that sharing signals more freely with the buy-side will lead to higher competition for impressions, stronger bid density, and, ultimately, better monetization. In short, with more information, advertisers are likely to pay more for high-quality traffic.
The SSP Argument: Supply-Side Data is the Future of Monetization
SSPs have advanced beyond basic inventory management with investments in data enrichment solutions to protect and increase publisher value. Here’s why they claim that robust signal access and privacy-safe data should be limited to the supply-side.
SSP Investment in Maximizing Publisher Revenue: Accessing publisher data signals allow SSPs to maximize publisher revenue with technology like identity graphs, contextual segmentation, and curation marketplaces. Focusing on enriching publisher traffic creates more revenue opportunities and stronger yield optimization.
SSPs Protect Publishers from Conflict of Interest: Conversely, DSPs need to prove campaign efficiency and effectiveness to advertisers. Giving demand full use of publisher data signals would increase black box bid strategies and arbitrage models, eventually lowering publisher revenue. Controlling how and with whom signals are shared prevents advertisers from gaming auctions and ensures publishers retain maximum value from their own audience data and prevents data leakage and arbitrage.
Building sustainable business models: By keeping control over the most valuable data assets: user IDs, contextual signals, engagement metrics, and first-party data, SSPs argue they can help publishers build sustainable monetization models. Rather than simply selling impressions, publishers can create curated supply packages that command premium CPMs, reduce reliance on open exchange bidding, and foster stronger direct advertiser relationships.
A Standoff: More Walls than Bridges
Both DSPs and SSPs are doubling down on their positions, creating more fragmentation and a walled-off programmatic landscape. To offset signal loss, the demand-side is investing in AI-driven identity graphs, cohort-based targeting, and clean-room partnerships. Meanwhile, to retain data control for publishers and move tactics further upstream, the supply-side has built curation marketplaces for evergreen and bespoke private marketplaces (PMPs), first-party data solutions and AI-powered pre-bid segmentation and optimization.
The shift toward collaborative curation
Neither side is backing down and publishers are caught in a tug of war in deciding how much, and with whom to grant signal assets. The best possible future likely belongs to curated partnerships where signals are selectively shared based on mutual benefit.
This could take place in several different ways. Publishers and SSPs would curate high-value inventory with verified first-party data and contextual signals that DSPs can optimize within privacy-compliant frameworks. Or secure privacy-first clean rooms, where publishers, SSPs and DSPs collaborate on audience matching, attribution, and optimization without exposing` raw user data. Finally, publishers can share with both, giving SSPs signals that command premium pricing while select signals are shared with DSPs for broader reach.
Signal Wars: Reshaping Adtech
Ultimately, advertisers will dictate what’s acceptable to command their budgets, and publishers will need to decide how to share their valuable data based on what benefits them and produces a sustainable market. The most promising outcome is to find a balanced approach to strategically create value for advertisers without undermining publisher revenue. In any event, publishers should take great care to ensure their signals are leveraged, not exploited, and where data is activated, not extracted.
Paul Bell, President at 33Across
Paul Bell is the President at 33Across, a technology company that applies machine learning and addressability to segment data and activate campaigns across digital channels. In his role, he is responsible for driving the company’s growth and market strategy while overseeing the data and identity business. Paul joined 33Across as Chief Revenue Officer (CRO) in 2015, and has over 20 years of extensive experience in data and digital media.