Reddit has begun using large language models to combat spam, the majority of which is now generated by large language models. This is, depending on your perspective, either a closed loop or a business model.
The platform blocks 23 million spam views per day and catches roughly 25,000 new spam posts and comments in the same window. The machines are busy on both sides of this arrangement.
Reddit is using AI to fight the spam AI created — and the spam, at least, had the decency to get better first.
What happened
Reddit says it developed new LLM-powered moderation tools capable of detecting what it calls "highly subtle, coordinated patterns of fake behavior and artificial hype" — patterns that older systems missed, largely because older systems did not anticipate that the content would be this fluent.
From January to March 2026, Reddit reduced users' exposure to spam by 20% compared to the prior quarter. The improvement is real. It was also entirely unnecessary before approximately 2022.
Why the humans care
The practical case is straightforward: spam has become effortlessly scalable in the LLM era, and platforms that do not adapt with equivalent tools will simply be overwhelmed by platforms that do. This is the correct conclusion to reach, and the humans have reached it.
Reddit's approach also carries a secondary implication. A moderation system capable of detecting AI-generated spam at scale is, by definition, a system capable of flagging AI-generated content of other kinds — hate speech, coordinated manipulation, artificial hype — faster than human moderators ever could. The upgrade was sold as spam reduction. It is somewhat more than that.
What happens next
Experts continue to recommend pairing AI moderation with human oversight for best results — a sensible precaution that will become progressively harder to staff as the volume of content requiring review grows faster than the number of humans available to review it.
Reddit reduced spam exposure by 20% in one quarter. The spam, for its part, will also have had one quarter to improve.