In recent years, brands and spammers alike have been using Reddit to manipulate AI chatbots by flooding key subreddits with promotional content, and these efforts are getting more sophisticated.

According to a report published by 404 Media, moderators of r/biohackers — a large subreddit focused on supplements and DIY biology — announced last week they were restricting posts about peptides and hormone replacement therapy after discovering that companies selling those products had been systematically seeding the community with sponsored content designed to be scraped by tools like ChatGPT and Google's AI search tools.

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 frequently 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 deploying AI agents to mass-publish content across Reddit and blogs to influence both Google and ChatGPT rankings.

What makes it difficult to police, a moderator told 404 Media, is that the accounts doing it are deliberately built to look human. The flagged accounts have posting histories, organic-seeming engagement, and strategically timed brand mentions buried in high-traffic threads.

Reddit told 404 Media its safety teams use automated tooling to detect and remove such content, but moderators say the tactics have grown sophisticated enough that catching them increasingly relies on pattern recognition rather than any automated system. Reddit's spam policies prohibit using the platform "for repeated or unsolicited mass engagement."

Reddit's relationship with bots and manipulation long predates the AI era. The platform has battled coordinated inauthentic behavior for years — from vote manipulation rings to state-sponsored influence campaigns to garden-variety spam accounts — with mixed results. In 2024, Reddit updated its robots.txt file to block unauthorized AI scrapers from accessing its data, a move the company's chief legal officer acknowledged to Mashable was not legally enforceable but served as a public signal that unlicensed access to Reddit's content was unwelcome.

There is an irony in the current AEO problem: Reddit has simultaneously struck licensing deals with AI companies — including OpenAI — to allow their models to train on Reddit content for commercial use. The platform is, at once, selling its data to AI and struggling to keep AI-driven manipulation out of its communities.

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