Two-thirds of consumer attention lives on the open internet, but only one-fifth of ad spend follows it there. That gap is no accident. Walled gardens spent the past decade creating it.
But now the gap is about to close. Better data, real investment in AI, credible measurement and market consolidation are giving the open internet the tools to finally prove that it can compete with walled gardens on outcomes, not just reach.
Open internet publishers collectively reach audiences at a scale that exceeds any closed platform. Fragmented technology stacks, point solutions and limited visibility into outcomes, however, have made it structurally difficult for open internet players to connect the right advertiser with the right audience. Inventory that is fragmented or cannot demonstrate its value attracts less demand, which results in lower CPMs.
This spend imbalance partly comes down to pricing. Published benchmarks show advertisers pay roughly double on average for equivalent reach inside walled gardens compared to the open internet. But the imbalance is also a result of walled gardens using their reach and data power to attract more budget. The challenge for open internet players has never been supply, but rather the infrastructure and data required to show what that supply is actually worth.
Those weaknesses are now being solved.
Outcomes now matter more than media costs #
For most of the history of programmatic advertising, the dominant advertiser question was about cost-efficiency: How cheaply can I buy media? This shaped the entire technology stack – from DSPs and SSPs to exchanges and data – around cost reduction and scale and made walled gardens attractive for the same reason. Owning substantial publishing assets gave walled gardens the ability to deliver on that demand. However, the question that leading advertisers should ask is changing. It’s no longer “How cheaply can I buy media?” but “What business result did this investment actually create?” Whether the objective is customer acquisition, market share, brand perception or sales, the conversation has shifted from media cost to measurable impact and outcomes. When outcomes are the currency, the ability to demonstrate performance matters more than cheap inventory, and the open internet has a stronger performance case to make.
Trust in walled gardens is eroding #
For years, walled gardens were treated as the reliable part of the programmatic spectrum – think precise targeting, easier attribution and measurable reach – which made it easy for advertisers and their agencies to spend substantial media budgets without having to deal with multiple smaller-scale open internet point solutions. But as the open internet improves its weaknesses and increases transparency, such as through recent upgrades to supply-chain visibility, the relative advantage of closed environments continues to narrow. Even the platforms themselves appear to recognize the problem.
Advertisers are becoming more critical of the context in which their ads appear within walled gardens. In June, AppsFlyer announced it had secured more than $1 billion in investment from Google, Meta, Moloco and Unity at a $2.7 billion valuation to build independent, AI-powered ad measurement. AppsFlyer stated publicly that none of the investors receives preferential access to its APIs, measurement signals, attribution logic or commercial terms. In short, four major ad tech players just paid a premium for a minority stake in measurement infrastructure they explicitly do not control, a concrete signal that they know grading their own homework is no longer sufficient on its own. Independent, verifiable measurement is a critical piece of shared infrastructure.
The data advantage is narrowing #
Advances in AI, contextual intelligence, SDK-driven intent signals, privacy-first identity solutions and access to search intent signals and LLM conversational data are giving open internet platforms meaningfully better tools to predict audience behavior and likelihood to convert, and to connect ad exposure to outcomes. As these capabilities mature, the distinction between open and closed ecosystems becomes less about data availability and more about how effectively signals are activated.
As we argued in our recent AdExchanger piece on why the future of bidding won’t be won by DSPs alone, the supply side is no longer just a pipe. SSPs with direct publisher relationships and access to SDK-level data sit on genuinely predictive signal sets. This advantage only compounds as AI gets better at activating them.
Integration is becoming the edge #
The open internet ecosystem was built around a deliberate separation between buy-side and sell-side technology. That separation no longer makes sense. Visibility across both demand and supply, combined with eliminating the cost of unnecessary intermediary platforms, creates advantages that point-solution providers cannot easily replicate.
Stronger demand attracts better supply. Richer supply generates better data. Better data improves advertiser performance. The flywheel increasingly favors platforms that have invested in closing the loop across demand, supply, data and performance.
Consolidation is accelerating #
The open internet remains fragmented, but consolidation is already underway. As AI capability, measurement infrastructure and data partnerships become table stakes, the market is separating platforms that can operate at scale from those that cannot.
The result will be a smaller number of larger and more capable companies, ones that can credibly compete with walled gardens on outcomes while preserving the diversity and publisher plurality that make the open internet worth competing for.
The path forward will be determined by who builds the strongest connection between advertisers, publishers, data and verifiable outcomes. The open internet has always had the raw material. In the new intelligence era, open internet players with scale, rich data and an AI-first approach are closing the outcomes gap with walled gardens fast enough to give advertisers a real alternative.
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