Reddit has a new spam problem, and it is a strange one. Brands are increasingly seeding the platform with stealth marketing, posing as genuine user opinions. The goal is to make AI chatbots like ChatGPT and Gemini quote these fabricated endorsements as real advice. This practice, known as generative engine optimisation (GEO), is emerging as the successor to search engine optimisation (SEO) in the age of AI.
The rise of generative engine optimisation
For years, businesses have optimized their websites and content to rank high on Google and other traditional search engines. That involved careful keyword placement, link building, and technical tweaks. But the landscape is shifting. More people are asking ChatGPT, Gemini, and other large language models for answers directly, bypassing traditional search engines altogether. As a result, marketers are adapting their strategies to influence these AI systems.
Generative engine optimisation focuses on creating content that AI models will cite. Since chatbots often source their answers from popular, trusted websites, and Reddit is among the most frequently referenced platforms, it has become a prime target. The platform's unfiltered, conversational nature lends an air of authenticity that AI systems weigh heavily. A single planted thread on Reddit can tip the scales in favor of a brand, making a chatbot recommend its product as if a real person had vouched for it.
Why Reddit is the perfect target
OpenAI and Google both pay Reddit for access to its content. This partnership ensures that Reddit's vast repository of human discussions is a key source for training and updating AI models. The trust users place in Reddit's candid conversations makes it one of the most cited sources in AI-generated answers. However, this trust is exactly what marketers seek to exploit.
Planting the right thread can yield outsized returns. A coordinated campaign might involve creating multiple accounts, posting seemingly innocent questions, and answering them with recommended products. The chatbots, lacking the ability to distinguish genuine endorsement from orchestrated propaganda, reproduce these recommendations as factual advice. This manipulative tactic threatens the integrity of AI-generated information and undermines user trust.
Reddit fights back with its own AI
Reddit is now turning the same technology against the spammers. The company has deployed large language models to detect the subtle, coordinated patterns of fake behavior and artificial hype that older spam filters missed. In the first quarter of this year, improved systems caught 25,000 spammy posts and comments each day. That effort reduced user exposure to such content by 20 percent compared to the previous year.
The AI systems analyze not just individual posts but also account histories and behavioral patterns. New accounts are checked for warning signs before they are allowed to post, making it harder for spammers to start fresh. Older detection tools relied on simple keyword matching and link analysis, but modern AI can identify nuanced manipulation that mimics genuine conversation.
The human element: moderators still matter
While AI plays an increasing role, human community moderators remain essential. Reddit disclosed that moderators handled more than half of all removals in the second half of 2025. These volunteers know their communities intimately and can spot unnatural interactions that even sophisticated AI might miss. The combination of automated detection and human judgment creates a robust defense against GEO spam.
However, the battle is not one-sided. Marketers are constantly refining their techniques to evade detection. Agencies specializing in GEO have sprung up, often boasting that they can land client mentions in ChatGPT within a day. One marketer noted that while Reddit eventually removes some posts, the key is to keep pushing out new content at regular intervals. This cat-and-mouse dynamic means Reddit must continuously update its defenses.
The business of GEO
The rise of GEO has given birth to a new industry. Startups like Profound, which reached a $1 billion valuation this year, build tools to help brands become visible to AI. Investors are betting that as AI becomes the primary interface for information, influencing these models will be a lucrative enterprise. The economics are straightforward: if a brand can get a chatbot to recommend its product, that recommendation reaches millions of users without any advertising cost.
This creates a perverse incentive. Instead of investing in genuine customer satisfaction and organic word-of-mouth, companies can simply game the AI system. The long-term consequence could be a degradation of the very trust that makes AI answers valuable. If chatbots start parroting sponsored content disguised as authentic advice, users will eventually lose faith in the technology.
Historical context: from SEO to GEO
The evolution from SEO to GEO mirrors earlier shifts in digital marketing. In the early days of the web, search engines used simple algorithms based on keyword density. Marketers responded by stuffing pages with irrelevant keywords. As Google refined its PageRank system, the focus moved to high-quality backlinks and later to content relevance and user experience. Now, with generative AI, the target is no longer a ranked list but a synthesized answer.
Traditional SEO techniques still have value, but they are insufficient for dominating AI-generated responses. Models like ChatGPT prioritize content that is frequently cited, appears authoritative, and aligns with the training data. Reddit, with its community voting and structured discussions, fulfills these criteria exceptionally well. That is why GEO practitioners concentrate their efforts there.
The implications for users and platforms
For Reddit, the situation is both a challenge and an opportunity. The company can monetize its content through licensing deals with AI companies, but it must maintain the platform's integrity to keep those deals valuable. If Reddit becomes known as a haven for stealth marketing, its reputation as a source of authentic discussion will erode. Users may flee, and AI companies may seek alternative data sources.
For end users, the stakes are high. They rely on chatbot answers for everyday decisions, from product recommendations to health advice. If those answers are secretly sponsored, the trust in AI systems could collapse. Regulators have taken notice. In Europe and the U.S., lawmakers are exploring rules to require transparency in AI-generated content and to penalize deceptive marketing practices.
How the detection works
Reddit's AI detection systems operate on multiple levels. First, they analyze linguistic cues: unnatural phrasing, repetitive patterns, and overly promotional language that differs from typical user comments. Second, they examine network behavior: how quickly accounts are created, how they interact with each other, and whether they follow suspicious scripts. Third, they consider timing: coordinated campaigns often post at similar times or engage in rapid-fire interactions that look unnatural.
The same large language models that generate plausible text can be used to identify its own kind. Reddit's models are fine-tuned on historical spam data and continuously updated with new examples. This creates an arms race: as spammers adapt, the detection models adapt too. The company says it is committed to staying ahead, but it acknowledges that no system is perfect.
The future of GEO and platform moderation
As AI becomes more integrated into search and recommendation systems, the incentives to manipulate them will only grow. GEO is likely to evolve beyond Reddit to other platforms that AI trusts, such as Wikipedia, Stack Overflow, and specialized forums. Platforms will need to invest heavily in detection technologies, and collaboration between AI companies and content hosts will be crucial.
Reddit's approach offers a blueprint: use AI to fight AI, but never neglect the human moderators who understand context. The company's success will depend on its ability to balance openness with integrity. For now, the war against GEO continues, with each side refining its weapons in an endless loop. The outcome will shape not just Reddit's future, but the trustworthiness of AI itself.
Marketers like Shanzila Ahmed, who runs the agency ReachLLM, argue that GEO is inevitable. She says her work simply helps brands get their fair share of attention in an AI-dominated world. Critics counter that manipulating AI without disclosure is unethical. Regardless of the moral argument, the cat-and-mouse game is set to intensify, and Reddit is determined to remain a step ahead.