How often Reddit comments call things "AI slop" or "written by AI"

What we counted

We took the same 100 large English-language subreddits as in our em dash study and searched every comment written there from January 2021 to September 2026: 634,902,252 comments in all. We looked for two things. The first is the phrase "AI slop". The second is the older ways of saying something was made by AI: "written by AI", "written by ChatGPT", "sounds like AI", "sounds like ChatGPT", "reads like AI", "reads like ChatGPT", "ChatGPT wrote", "AI wrote this", "clearly AI", "obviously AI", "this is AI", "AI generated post" and "AI-generated post". Matches are whole words and ignore case, so "AI slop" counts and "AI slope" doesn't.

We count threads, not comments. A thread counts in a given month if at least one comment written under it that month has a match, and the share is out of all threads that got any comment that month. One person posting "AI slop" ten times in a thread counts once, and a busy thread doesn't count more than a quiet one. Comments posted with the moderator badge are left out, because some subreddits put "AI slop" in their rule reminders: in 2026 that was 1,128 of 48,315 comments with the phrase (2.3%).

"AI slop" barely existed on Reddit before 2024

In 2021, 97 of 5,597,691 threads in our sample had a comment like this, about 1 in 58,000, and none of them said "AI slop". The phrase shows up in 2 threads in 2022 and 24 in 2023. In 2024 it was in 1,078, still only 0.018% of threads. Then it took off: 0.20% of threads in 2025 and 0.55% in the first nine months of 2026.

The older phrases moved first. ChatGPT went public on November 30, 2022, and the next month the share of threads with "written by AI", "sounds like ChatGPT" and the rest went from 0.011% to 0.034%, 3.1 times as high. They kept climbing slowly after that, to 0.231% of threads in 2026.

"AI slop" passed the older phrases in April 2025

In March 2025 the two were nearly even: "AI slop" was in 0.105% of threads and the older phrases in 0.110%. In April 2025 "AI slop" moved ahead, 0.151% to 0.125%, and it has stayed ahead every month since. In 2026 it was in 0.55% of threads, 2.4 times as often as all the older phrases together.

The older phrases didn't fade. They kept growing while "AI slop" grew faster, which looks less like one phrase replacing another and more like a new, shorter word for a reaction that was already common. "Written by AI" is a claim about where a text came from. "AI slop" also says what the commenter thinks of it, and it works for images and videos as well as text.

Counted per comment, the rise has slowed

Since December 2025 the share of threads with "AI slop" has kept climbing, from 0.38% to 0.71% in September 2026. Counted per comment, it has been much flatter over the same months: between 378 and 475 comments per million each month.

Most of the gap comes from threads getting more comments. The average thread in our sample got 19.0 comments in December 2025 and 26.5 in September 2026 (counting only the comments written that month), and a thread with more comments is more likely to have one that says "AI slop". So the phrase is still spreading across threads, but people aren't saying it much more often per comment than they did at the end of 2025.

It went up almost everywhere

80 subreddits in the sample had at least 2,000 threads both in 2021 and in 2026. The share of threads with one of these phrases went up in 79 of them. The one exception, r/borrow, had none in either year. In the median subreddit of the 80, 0.47% of threads in 2026 had a match.

The leaders are far above that. In r/technology, 9.1% of threads in 2026 had a comment calling something AI, and in r/interestingasfuck 7.8%: one is mostly tech news, AI included, and the other a feed of viral pictures and videos. At the other end are subreddits where people mostly ask for help or arrange things with each other, like r/mushroomID, r/borrow and r/PokemonGoRaids, where it almost never comes up.

What a match means

A phrase count isn't a count of AI posts, so we read a random sample of 50 matching comments from July to September 2026. In 30 of them the commenter was pointing at something in the thread itself: the post, a picture in it or another comment. Most of these are short verdicts like "AI slop" or "this is AI". In 4 the commenter was asking whether something was AI or arguing that it wasn't. The other 16 were about AI content in general, somewhere else, or a joke.

So roughly three in five matches are a call about the thread, and the rest show how much AI comes up in conversation. Neither kind tells us whether anything in the thread was actually made with AI. We didn't check, and from comments alone we couldn't.

What this data can't tell you

• Whether a post was made with AI. A match means someone said it, not that it's true, and some comments in our sample argued the opposite.
• Every other way of saying it. Our list misses "slop" on its own, "bot", "fake" and new phrases as they appear, and the older phrases include some loose ones like "this is AI". The numbers are best read as a trend, not a complete count.
• The early years rest on small numbers: 97 threads in 2021 and 440 in 2022. The "1 in 58,000" for 2021 would move a lot with a few dozen threads more or less.
• October 2025 is left out, as in our em dash study, where that month's data looked wrong. Here its numbers sit between the months around it, so leaving it out changes little.
• Threads got more comments in August and September 2026 (25.7 and 26.5 on average, against at most 22.1 in any earlier month), which pushes the share of threads up. The per-comment count above doesn't have that problem.
• The 100 subreddits were picked by how active they are today, so some barely existed in 2021. The comparison by subreddit only uses those with enough threads in both years.

Method

Subreddits

We started from the 400 most active English-language subreddits with at least 200,000 subscribers, leaving out NSFW and non-public ones, ranked by recent posting volume. The 100 in this study are every fourth subreddit on that list, the same sample as the em dash study.

Comments and phrases

Every comment in those subreddits from January 1, 2021 to September 30, 2026, of any length, except comments distinguished as moderator posts. "AI slop" and each older phrase ("written by AI", "written by ChatGPT", "sounds like AI", "sounds like ChatGPT", "reads like AI", "reads like ChatGPT", "ChatGPT wrote", "AI wrote this", "clearly AI", "obviously AI", "this is AI", "AI generated post" and "AI-generated post") must appear as whole words; case is ignored.

Threads and months

Each comment goes into a month by its creation time in UTC. For each subreddit and month we count the threads that got at least one comment, and the threads where at least one of those comments has a match. A year adds up its months, so a thread that gets comments in two months counts in both. On the line chart each value sits at the end of its month.

The sample of matches

We drew 50 matching comments from July to September 2026 at random (by a hash of the comment ID) and sorted each into one of three groups by reading it: about something in the thread, questioning whether something is AI, or about AI in general. A few were judgment calls.

Source

Public Reddit archives back to 2005, plus our own collection for recent months. All counts come from one set of queries run on October 23, 2026. If you spot a mistake, tell us and we'll fix it here with a dated note.

Questions people ask

The data

The monthly and per-subreddit counts behind this article are in these files. They're free to reuse under CC BY 4.0; please credit KissMyPost and link to this page.

• CSVMonthly counts, January 2021 to September 2026Comments, threads with comments, and comments and threads with "AI slop" or one of the older phrases, by month. October 2025 is flagged and left out of the article.
• CSVCounts by subreddit, 2021 and 2026All 100 subreddits in the sample: threads with comments and threads with a match, for 2021 and January to September 2026, with "AI slop" and the older phrases split for 2026.
• PNGMain chart, 1600 × 1000The chart on this page as an image.

This study comes from the archive behind KissMyPost, a Reddit analytics tool. It shows what kind of posts do well in a subreddit, who writes there and when, and lets you search posts back to 2005.