The news: AI slop accounts for a relatively small share of ad spend, but it’s exposing the limits of traditional ad quality metrics, per an analysis by the Trustworthy Accountability Group (TAG), the Association of National Advertisers (ANA), and Fiducia.

• This low-value AI-generated content makes up between 1.3% and 2.4% of measured open-web programmatic spend. However, it had higher viewability than clean inventory (77.2% versus 74.9%), and after measurability was factored in, it was classified as premium more than 70% of the time.
• AI slop’s invalid traffic (IVT) rate is just 0.05%, compared with 0.32% for clean inventory.
• 88% of AI slop is also identified as made-for-advertising (MFA) content, falling into common “content farm” categories like recipes, personal finance, and how-to topics.

What it means: The metrics that advertisers use to judge quality aren’t penalizing content that has little to no value to consumers and might even dissuade viewers from trusting adjacent content.

AI slop introduces a novel risk when brand ads appear on inventory that’s technically brand safe—e.g., doesn’t contain inappropriate material—but is seen as low-quality or misleading.

The fact that AI slop has higher viewability, lower IVT rates, and is often ranked as premium breaks down traditional quality signals and challenges how programmatic buying works. If low-value AI content can score better than inventory from quality publishers, optimization systems may be choosing the wrong inventory.

Implications for marketers: Advertisers and verification vendors will need a new measurement layer if viewability, IVT, and impressions aren’t sufficient proxies for content quality.

That creates an opportunity—and perhaps a future spending category—for AI-content detection and quality scoring. AI slop’s growing presence will shift attention to content authenticity, originality, and optimization systems that can distinguish meaningful content from AI-generated engagement bait.

Dive deeper: Get more programmatic insights from our US Programmatic Advertising Forecast and Ad Tech Trends H2 2026 report.

This content is part of EMARKETER’s subscription Briefings, where we pair daily updates with data and analysis from forecasts and research reports. Our Briefings prepare you to start your day informed, to provide critical insights in an important meeting, and to understand the context of what’s happening in your industry. Non-clients can click here to get a demo of our full platform and coverage.