Your Ad Blocker Might Be Making Your Internet Experience Worse

Adblock Plus Users See 14% More Problematic Ads Than Everyone Else

NEW YORK — Internet users who install ad-blocking software to escape annoying advertisements may actually be seeing more problematic content than people who browse without any protection at all.

Researchers at New York University discovered that users of Adblock Plus — one of the world’s most popular ad-blocking extensions — encounter 13.6% more problematic advertisements on average compared to people browsing without any ad blocker. This challenges the core promise of ad-blocking technology: that it automatically creates a safer, cleaner online experience.

The study examined Adblock Plus’s “Acceptable Ads” feature, which allows certain ads to bypass the blocker if they meet specific formatting standards. Since this feature is enabled by default, millions of people believe they’re getting safer advertising when they may actually be seeing more deceptive, annoying, or inappropriate content.

How Researchers Tested ‘Acceptable’ Online Ads

The research team collected over 18,000 ads from 4,710 web pages, using automated crawlers that simulated real users in the U.S. and Germany, including both adults and minors. They developed a seven-category system for identifying problematic content, covering deceptive claims, manipulative design, user disruption, inappropriate material, political topics, regulatory violations, and more.

Seven trained researchers reviewed and annotated 1,200 unique ads to establish a ground truth dataset. An AI model then analyzed thousands more ads using the same taxonomy to detect patterns.

The Troubling Numbers Behind ‘Better’ Ads

The increase in problematic ads wasn’t small. For U.S. users, the volume of problematic content jumped 17.6%. Most concerning, users under 18 years old saw a 21.8% increase in problematic content when using Adblock Plus. The study found that about 9.6% of ads shown to minors violated regulations by promoting age-inappropriate products like alcohol, gambling, or dating services — a figure that rose to 10.7% with Acceptable Ads enabled.

Users with Adblock Plus encountered more advertisements with false health claims, manipulative design tricks, political ads, and content that disrupted their browsing experience. While Adblock Plus did reduce the total number of ads shown — fulfilling its promise to decrease “ad clutter” — the ads that survived the filter were more likely to be problematic.

Some advertising networks appear to serve different — and worse — content to users they detect are using ad blockers, suggesting possible differential treatment rather than confirmed deliberate targeting. The researchers noted that this pattern could enable new fingerprinting and tracking techniques.

Why ‘Acceptable’ Online Advertising Standards Fall Short

The root of the problem lies in how the Acceptable Ads program operates. Companies pay fees to have their ads included on Adblock Plus’s allowlist, but the standards mainly focus on visual format rather than content quality. This creates a situation where legitimate advertisers may avoid the extra fees, while questionable advertisers see an opportunity to reach users who specifically tried to avoid bad ads.

Individual ad exchanges included on the allowlist showed up to 34% more problematic content when serving ads to Adblock Plus users, compared to unprotected browsers — raising questions about whether these networks treat privacy-aware users differently.

The Broader Problem With Ad Blockers

These results fit a troubling pattern: tools designed to protect users often backfire. Previous studies show that people who reject cookie tracking face more aggressive tracking attempts, and those who decline data sharing often encounter steep paywalls or worse user experiences. The paper also highlights how the prevalence of unique, low-quality ads could be used to fingerprint privacy-focused users, revealing whether someone is running Adblock Plus.

Notably, German users saw only a 5.3% increase in problematic ads — a statistically insignificant change — suggesting that stricter privacy laws like the GDPR may help limit some of these problems.

For millions of people who installed ad-blocking software to improve their online experience, these results reveal a hidden cost: the tools marketed as protection may actually make the internet worse for the people who most want to avoid its problems.

Disclaimer: This summary is based on “Sheep’s clothing, wolfish impact: Automated detection and evaluation of problematic ‘allowed’ advertisements” by Roongta et al. The study focused on Adblock Plus’s Acceptable Ads feature as of October 2024 in the U.S. and Germany. Findings may not apply to other tools or future versions. Always read the full paper for detailed methods and limitations

---