Reddit Says AI Blocks 23 Million Spam Views a Day—Without Showing Its Error Rate

• Reddit says upgraded automated systems block 23 million spam views, catch about 25,000 net new spam posts and comments, and revoke nearly 2 million inauthentic votes each day.
• Its reported 20% reduction in spam exposure compares January through March 2026 with the preceding three months; several reports incorrectly described it as year over year.
• Reddit has not disclosed what share of the caught material was AI-generated or published spam-specific precision, recall, appeal or reinstatement rates.
• AI answer providers remain a second control point: a Cornell Tech preprint found sharply different rates of user-generated citations across the systems it examined.

Reddit has added large language models to its spam defenses as marketers try to seed apparently ordinary recommendations for AI answer engines to retrieve. The company’s new figures establish the scale of its enforcement. They do not establish how accurately the system separates coordinated promotion from genuine enthusiasm.

Big enforcement numbers with small denominators

Reddit said in its July 6 announcement that it evaluates signals when an account is created and uses LLMs to detect coordinated fake behavior and “artificial hype” that older systems missed. Accounts suspected of automation may also be required to verify that they are human.

The company reported five results from the upgraded systems:

These units answer different questions. A blocked view is prevented exposure; a caught post or comment is a content action; a revoked vote is an engagement action. Without common denominators, they cannot be combined into a spam-prevalence or filter-accuracy rate. Reddit reported 121.4 million average daily active uniques for the final quarter of 2025 in its annual filing, but that user count is from another period and is not a denominator for daily blocked views.

The comparison period also matters. The company’s 20% figure is sequential, not year over year, despite that description appearing in some coverage. Nor did Reddit say that all, most or any measured share of the caught spam was created with an LLM. The announcement identifies LLMs as a detection tool; it does not quantify AI-generated spam.

Reddit published another set of results for a separate expansion of automated enforcement against hate and violence in English-language text. It said average time from detection to enforcement fell below five seconds, enforcement actions increased by more than 200%, exposure declined by more than 40% and false positives fell by more than 40%. Those claims do not supply an error rate for spam, and Reddit did not provide underlying counts or an independent evaluation for either program.

Reddit’s company-reported global quarterly average daily active uniques reached 121.4 million in Q4 2025, comprising 50.7 million logged-in and 70.7 million logged-out users. Source: Reddit 2025 Form 10-K.

The harder target is manufactured consensus

Bots and spam are not new to Reddit; the company says it has dealt with them throughout its 21-year history. What has changed is the potential audience for a planted recommendation. A promotional comment can influence a person reading a thread and, if retrieved later, an AI system assembling an answer.

Marketers call the practice generative engine optimization, or GEO. ReachLLM founder Shanzila Ahmed told Bloomberg that her agency had produced Reddit posts for brands that ChatGPT cited, sometimes within a day, while Reddit later removed some of the same posts. She also described creating narrowly focused subreddits for clients and acknowledged that stronger enforcement raised the risk of account suspension, according to the retained report.

That account shows why votes matter alongside text. A campaign can manufacture not only a recommendation but the appearance that a community endorsed it. Reddit says it has been revoking nearly 2 million inauthentic votes a day, but it has not said how many were associated with GEO, how many campaigns were disrupted or how often legitimate promotion was misclassified.

The classification problem does not have a simple textual boundary. A paid recommendation can be written to resemble an ordinary opinion, while a real user may repeatedly advocate for a product without compensation. Reddit’s filing warns that defects in automated systems can make it difficult to separate objectionable from permissible content. It also says banned actors can create new accounts and repost removed material.

That is why Reddit’s sitewide models are not a complete substitute for local moderation. The company says its safety staff combine automation with human review, while volunteer moderators apply community rules and users rank material through voting. Reddit’s reported transparency data for July through December 2025 show that community moderators were responsible for more than 52% of post and comment removals, as the account of those data explains.

Cornell Tech researchers’ WARP schematic shows how altered Reddit content retrieved by deep-research agents can flow into a generated answer. Source: Cornell University preprint.

AI answer engines choose how exposed they are

A Cornell Tech preprint supports the concern that editable web pages can steer deep-research agents, but its scope is narrower than a general claim that Reddit can manipulate every chatbot.

The researchers deliberately built a dataset around advice and recommendation queries likely to surface user-generated content and to cause harm if manipulated. They tested 176 queries in 11 topic clusters, sampled from a larger catalog. The three open-source systems—STORM, Co-STORM and OmniThink—used the same Serper search interface and GPT-4o-mini in the experiment.

Across those three systems, user-generated platforms supplied 17% to 23% of retrieved URLs, and Reddit accounted for 54% to 71% of that subset. A short, simulated poisoned passage attached to a page the systems already retrieved could cause them to mention a fictional entity. With a roughly 13-word passage targeting one URL, mention rates conditional on the poisoned source being exposed ranged from about 38% to 51%. When the researchers appended longer passages to full Reddit threads and targeted three URLs, conditional mention rates ranged from about 30% to 53%.

Those were controlled simulations, not live attacks. The researchers did not publish poisoned material on the web and did not run end-to-end attacks against OpenAI Deep Research or Gemini Deep Research. They could observe only the citations, not all retrieval, of the commercial systems. Even within the selected query set, cited user-generated URLs varied sharply: 3 of 748 citations for OpenAI Deep Research, or 0.4%, versus 623 of 5,157 for Gemini Deep Research, or 12.1%.

The difference redistributes responsibility. Reddit can act against coordinated promotion and fake votes on its platform. AI answer providers can decide which sources to retrieve, how to weight user-generated claims and whether to require corroboration before turning a forum comment into a recommendation. Blocking all user-generated sources is one possible defense, but the preprint warns that doing so also removes legitimate first-hand expertise and local knowledge.

Cornell Tech preprint results for cited URLs across 176 selected queries. For OpenAI Deep Research and Gemini Deep Research, the researchers could observe citations but not the systems’ full retrieval activity. Source: Cornell University preprint.

Trust supports advertising and licensing

Reddit has content agreements with Google and OpenAI, according to the reported account of its AI relationships. Keeping the corpus useful therefore has licensing value. The larger immediate stake, however, is advertising.

Reddit recorded $2.06 billion in advertising revenue out of $2.20 billion in total revenue in 2025—approximately 94%, up from 91% in 2024. Its filing describes content licensing as early-stage and says substantially all contract value associated with licensing revenue came from two partners. It does not separately disclose licensing revenue; “other revenue” also includes products sold directly to users, although the filing says those user-product sales were not material.

Authenticity consequently supports two businesses. Advertisers buy access to conversations Reddit presents as high-intent and trustworthy. Licensees buy access to a corpus Reddit presents as human-generated and continuously updated. Inauthentic posting, voting and ad engagement can damage both, and the company warns that manipulation can also produce incorrect advertising counts or charges.

The economics of the new spam system remain undisclosed. Reddit does not identify the models or model providers used for this enforcement, the compute cost, the volume of human review triggered, or the cost per prevented view. Its filing says the broader platform relies primarily on Amazon Web Services and Google Cloud Platform, but it does not allocate that infrastructure spending to spam detection.

The next disclosure must measure mistakes

Reddit’s next useful update would report more than enforcement volume. It would define a sampled population of posts, comments, votes or views; state the prevalence of spam within that population; and separate AI-generated material, coordinated commercial promotion and traditional automation.

Spam-specific precision and recall would show what the model catches and misses. Successful appeal and reinstatement rates would show the cost imposed on legitimate users. Results broken out by language, community size and enforcement stage would indicate where automation works and where moderators still carry the burden. An independent audit or reproducible sampling method would make changes over time comparable.

The company must also distinguish model improvement from changes in attacker volume. A lower exposure rate can reflect better detection, less attempted spam, changes in traffic or several effects at once. The answer-engine side needs parallel evidence: retrieval and citation rates for user-generated sources, corroboration rules, and measurements of whether manipulated claims reach final answers.

Blocking 23 million views a day is evidence that Reddit operates its defenses at scale. Until the platform publishes denominators and error rates—and AI answer providers disclose how they handle editable sources—the central question is not how much content the system touches, but how often it makes the right call.