Some Reddit comments tell you how the writer got there. "Google brought me here." "ChatGPT sent me here." I collected 19,749 of them, written between January 2025 and September 2026, and looked at the threads they sit in. What kind of thread is it? How old is it? Which subreddits get the most of them for their size? The full study with all the tables and CSVs has every number. Here I want to talk about the two things that surprised me.

The "best X" thread isn't special

I sorted every thread by its title. How-to and fix-it questions went in one pile, "best X" and recommendation requests in another, then alternatives, reviews, other questions and everything else. Then I compared the threads people say search sent them to with the thread of a typical Reddit comment. To keep it fair, I only kept threads older than 30 days on both sides, since young threads look different.

Here's what came out:

How-to threads are 11.6% of search arrivals and 6.6% of typical comments, so Google sends people to them 1.8 times as often. The "best X" threads barely move: 3.6% of search arrivals against 3.4% of typical comments. No lift at all.

So the thread that pulls people in from Google is someone asking how to fix a specific problem, in their own words. Think of a title like "iPhone won't charge after update", not a ranked list. I'll be honest, I expected the lists to win at least a little, since that's where I'd always assumed the buyers were. They don't.

That changed where I'd spend my time.

AI assistants lean the same way, though the sample is small. I only have 212 AI arrivals in threads older than a month, so I can't say AI avoids the "best X" threads. I can only say there's no sign it favors them.

AI finds threads while they're still warm

The second thing is about age, and this is where Google and the AI assistants part ways.

Search keeps old threads alive, and 41% of search arrivals land in threads more than a year old. So an answer somebody wrote ages ago can still be pulling in readers today.

AI assistants are different. Look at the youngest bar:

About a third of AI arrivals (34%) land in a thread less than a week old, against 16% from search. That's a big gap, but I'll repeat the caveat. AI arrivals are a small sample next to search, so treat the shape as rough.

One more thing worth knowing, because it's the part I keep coming back to whenever I look at this data. These comments show where people say an assistant or Google sent them, which is a different question from what ChatGPT cites. A thread can be quoted in an answer without anyone ever writing "ChatGPT sent me here" under it.

What I'd do with this

Answer the problem, not the list. Find the threads where someone describes the exact problem your product solves, because that's the kind of thread people get sent to. A "best X" thread draws them no more often than a random one.

Start with the product subreddits. 11 of the 25 subreddits with the most arrivals for their size are named after a product or company. Think r/applehelp, r/ios or r/firefox. If your competitor has a subreddit and people there ask how to fix things, you know where to look. You can see where a competitor's site gets linked on Reddit, by subreddit and month.

Don't skip old threads. A good answer in a two-year-old thread is still being read, because Google keeps sending people there.

Don't wait on new ones either. A thread from this week can already be where an assistant sends someone. So it's worth watching the subreddits where your buyers ask questions. If you don't know which ones those are yet, a free subreddit finder is a decent place to start.

Spread out. Almost every one of these threads (97.5%) has a single arrival. There's no one magic thread to win, just lots of small ones, and you get to them by being useful again and again.

What this can't tell you

I want to be clear about the limits. Only a small, unknown share of visitors ever comment, and fewer still say how they got there. If people who land in "best X" threads just read and leave, those threads are undercounted here, and I can't separate the two. The thread types come from title patterns too, which miss plenty of how-to threads whose title just describes the problem. An independent check without the patterns found the same direction, and stronger.

The method, the labeler check and all three CSVs are in the full write-up. If you spot a mistake, tell me and I'll fix it with a dated note. And if there's a question about Reddit traffic you'd like me to dig into next, tell me that too.

The short answer

In 100 large English-language subreddits, about 1 in 58,000 threads in 2021 had a comment saying "AI slop", "written by AI" or a similar phrase. In the first nine months of 2026 it was 1 in 143. "AI slop" barely existed on Reddit until 2024 and passed the older phrases in April 2025. In 2026 it was in 0.55% of threads, 2.4 times as often as all the older phrases together. The share went up in 79 of the 80 subreddits we could compare.

These are counts of words, not of AI posts. In a random sample of 50 matching comments, 30 pointed at something in the thread and the rest asked whether it was AI or talked about AI in general.

What we counted

We searched every comment written in 100 large English-language subreddits from January 2021 to September 2026: 634,902,252 comments in all. We looked for the phrase "AI slop" and for the older ways of saying something was made by AI, such as "written by AI", "sounds like ChatGPT", "clearly AI" and "this is AI". Matches are whole words and ignore case.

We count threads, not comments. A thread counts in a given month if at least one comment under it that month has a match. One person posting "AI slop" ten times in a thread counts once. Comments with the moderator badge are left out, because some subreddits put "AI slop" in their rule reminders.

"AI slop" barely existed before 2024

In 2021, 97 of 5,597,691 threads in our sample had a comment like this, 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%. They kept climbing slowly, to 0.231% of threads in 2026.

It 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.

The older phrases didn't fade. They kept growing while "AI slop" grew faster. That 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.

Where it went up

80 subreddits in the sample had at least 2,000 threads both in 2021 and in 2026. The share went up in 79 of them. The one exception, r/borrow, had none in either year.

The leaders are far above the median. In r/technology, 9.1% of threads in 2026 had a comment calling something AI, and in r/interestingasfuck 7.8%. At the other end are subreddits where people mostly ask for help or arrange things with each other, like r/mushroomID and r/PokemonGoRaids, where it almost never comes up.

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. 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.
• The early years rest on small numbers: 97 threads in 2021 and 440 in 2022.
• October 2025 is left out, as in our em dash study, where that month's data looked wrong.

Read the numbers as a trend, not a complete count.

Full method and data

The full method, all charts, and the CSV files with monthly counts and counts for all 100 subreddits are on the original page: How often Reddit comments call things "AI slop" or "written by AI".