AI is fueling Reddit’s spam problem

In recent years, brands and spammers have been using Reddit to trick AI chatbots by flooding important subreddits with promotional content, and these efforts are becoming more sophisticated.

According to a report published by 404 Media, the moderators of r/biohackers – a large subreddit focused on tools and DIY biology – announced last week that they were limiting posts about peptides and hormone replacement therapy after discovering that companies selling those products were systematically seeding the community with sponsored content designed to be deleted by tools like Google’s ChatGIPT.

The practice falls under the umbrella of Generative AI-engine optimization (GEO), or AI-engine optimization (AEO), an evolution of traditional search engine optimization (SEO). Because AI chatbots often draw on Reddit when generating responses, companies have identified the platform as a high-value target for shaping what those tools recommend.

Marketing firms have built entire service offerings around it. 404 Media identified one company, RedRover, that openly advertises sending AI agents to mass publish content across Reddit and blogs to influence both Google and ChatGPT rankings.

What makes it difficult for the police, the president told 404 Media, is that the accounts he creates are deliberately created to look like a person. Flagged accounts have post history, interactions that seem natural, and well-timed branding embedded in high-traffic threads.

Reddit told 404 Media that its security teams use automated tools to find and remove such content, but moderators say the tactics have grown so sophisticated that catching them increasingly relies on pattern recognition rather than any automated system. Reddit’s spam policies prohibit using the forum for “repetitive or unsolicited participation.“

Reddit’s relationship with bots and manipulation long predates the AI ​​era. The forum has battled targeted fake behavior for years — from vote-rigging threats to government-sponsored influence campaigns to garden-variety spam accounts — with mixed results. In 2024, Reddit updated its robots.txt file to prevent unauthorized AI scrapers from accessing its data, a move the company’s legal chief admitted to Mashable was illegal but served as a public signal that unauthorized access to Reddit content was unacceptable.

There is an irony in the current AEO crisis: Reddit has simultaneously reached licensing agreements with AI companies – including OpenAI – to allow their models to be trained on Reddit content for commercial use. The platform, at the same time, sells its data to AI and strives to keep AI-driven manipulation out of its communities.

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