Reddit faces a new wave of AI search spam

Reddit has become a prime target for marketers trying to influence AI-generated search results. Semrush data compiled for The Verge found that Reddit was the most-cited domain in May by ChatGPT, Perplexity, Google’s Gemini, and Google AI Mode—ahead of news publishers, scholarly repositories, and Wikipedia.

That visibility is changing the spam problem for Reddit’s volunteer moderators. Brands and agencies are now attempting to plant product mentions in communities whose value to AI systems comes from appearing independent, specific, and authentic.

How AI search turned Reddit into a marketing target

Users began adding “reddit” to searches to avoid low-quality search-engine-optimization results, and Google subsequently began linking to the platform prominently. Now, large language models frequently cite Reddit discussions when answering questions, while Google is showing AI Overviews more often for commercial searches involving product research and brand comparisons.

The result is a shift from traditional SEO to “answer engine optimization” and “generative engine optimization.” Some SEO experts cited by The Verge say a backlink may no longer be necessary for a company to appear in chatbot answers; a simple mention could be enough.

That has led to posts designed to look like ordinary conversations. A user might ask how people track their skincare routine, only for a series of replies to recommend an AI skincare app. Another post might ask about a heavily advertised brand, followed by a carefully phrased response praising it while acknowledging a minor drawback.

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The pattern surfaced in r/SkincareAddiction, where a user named Primary-Taro4254 repeatedly promoted Honeydew Labs' hypochlorous acid spray. The account cited the product’s 0.02% hypochlorous acid concentration and its acceptance by the National Eczema Association, while claiming it helped calm skin redness and irritation.

After users noticed similar endorsements across unrelated threads, a moderator warned the community about “marketing bots.” Moderators then took action against the account and began automatically filtering Honeydew Labs posts for review. Honeydew Labs did not respond to The Verge’s request for comment, and the Reddit user did not respond to a message.

Maya Adivi, a moderator of r/SkincareAddiction, says the tactics are becoming harder to distinguish from genuine participation. Older warning signs included overly enthusiastic reviews, tracking links, or product photos copied from a brand’s listings. Now, even a detailed explanation of a scientific study can attract suspicion if it appears to be part of a coordinated campaign.

“It’s a lot more subtle, but we’ve become more sophisticated as well.”

Moderators are filtering brands and suspected sock puppets

r/SkincareAddiction prohibits accounts affiliated with brands from posting. Moderators may warn some violators, but they more often ban brands and suspected sock-puppet accounts automatically. Adivi also removed a thread after learning that a marketing agency claimed it had “targeted” and “hijacked” the subreddit to promote an unknown Korean beauty brand and improve its Google ranking.

Other communities are reporting similar behavior. Users on r/CleaningTips have debated banning product names, while someone in r/BuyItForLife warned that the community was being brigaded by advertising bots to influence Google and AI results. r/FoodNYC’s self-promotion rules specifically address brands targeting old posts, and a moderator of r/salestechniques created a thread naming companies they believed were astroturfing.

The issue has also appeared in biohacking communities, where 404 Media reported promotional spam involving peptides. On the weight-loss subreddit r/loseit, moderator Dan told The Verge that he has found covert advertising for food-scanning apps, body-scanning scales, and GLP-1 providers. Moderators maintain a list of brands they believe are advertising secretly and automatically filter those names.

Dan says brand promotion often gives itself away through exact product names, dense keywords, and relentlessly positive language—details a normal user might not include when casually discussing a purchase.

“The main advantage that we have as people who are trying to stop [brands] from advertising is that they’ve got an agenda that a normal poster doesn’t have, and that is usually fundamentally what shines through and that’s how we spot them.”

Reddit and Google say they are fighting manipulation

Reddit said in early July that it was expanding its use of AI and large language models to detect “highly subtle, coordinated patterns of fake behavior and artificial hype.” The company said the upgraded systems catch 25,000 spammy posts and comments and block 23 million spam views every day.

Reddit evaluates accounts when they are created, looks for coordinated manipulation across accounts and conversations, and combines platform activity with user reports. Jared Nelson, the company’s senior director of global corporate reputation communications, declined to identify the specific signals its systems use, saying that would give spammers a way to evade detection.

“Every time bad actors change their playbook, we strengthen ours.”

Google spokesperson Jennifer Kutz told The Verge that forums contain both useful and low-quality user-generated content, and that Google’s systems are designed to distinguish between them. She also said Reddit receives “no special preference” in Google’s ranking system and that Google has maintained results that are 99% spam-free for years.

The company’s claims do not resolve the central problem: Reddit’s authority in AI search depends on the appearance of authentic, user-driven discussion, while marketers now have a direct incentive to manufacture exactly that appearance. Reddit says roughly 40% of discussions on the platform are commercial in nature, making the communities valuable both to shoppers and to companies trying to shape what chatbots say about their products.

The platform’s moderators are therefore no longer just cleaning up unwanted advertising. They are defending the source material that AI search systems increasingly treat as evidence—and the specific detection methods Reddit uses remain undisclosed.