Em dashes on Reddit have become 10 times more popular in a few years

We counted em dashes in 15.8 million long Reddit posts and 242 million long comments, from 2016 through September 2026. Posts changed a lot. Comments in the same subreddits changed far less.

By Dmytro Krutytskyi, KissMyPost Research·Published October 23, 2026·Updated October 24, 2026·Data through September 2026·15 min read

In 100 large English-language subreddits, the share of long posts containing an em dash rose from 0.70% in early 2021 to 6.53% in Q2 2025, more than nine times the early 2021 level. Long comments in the same subreddits went from 0.68% to 1.32%. The climb began in August 2024, about 20 months after ChatGPT launched, and it doesn't match the way phone autocorrect changed Reddit's punctuation in 2017. By month it peaked in July 2025 at 6.83% and fell 17% in August, when GPT-5 became ChatGPT's default. Em dashes haven't gone away since: the share bottomed out at 4.78% in December 2025, 30% below the peak, then rose to 6.26% in April 2026 and was 5.61% in September 2026, about 7 times the 2021 average of 0.75%. The rise is concentrated in posts, where text written elsewhere gets pasted in, which fits AI-assisted writing better than a keyboard change. It can't tell you whether any particular post was written by AI.

See when your subreddit is most active, what gets posts removed and what its readers talk about.

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Share of long Reddit posts and comments with an em dash, by quarter, 2016 to 2026Posts: 0.26% in Q1 2016, 0.70% in Q1 2021, 6.53% at the peak in Q2 2025, 5.57% in Q3 2026. Comments: 0.39%, 0.68%, 1.32% and 1.15% in the same quarters. Both lines rise slightly in late 2017; only posts rise sharply from mid 2024.1%2%3%4%5%6%7%201620182020202220242026iOS 11Sep 2017ChatGPTNov 2022GPT-5Aug 20256.5%CommentsPosts

100 large English-language subreddits. Posts and comments with 200+ characters. Source: KissMyPost analysis of public Reddit posts and comments.

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What we counted

We took 100 large English-language subreddits and looked at every text post and every comment of at least 200 characters written there from January 2016 to September 2026. That comes to 15,817,377 posts and 241,541,185 comments. For each one we checked a single thing: does it contain at least one em dash (Unicode U+2014, the long dash) anywhere in it. For posts, the title counts too.

Hyphens and en dashes don't count. The 200-character cut is there because a one-line comment rarely has room for any dash, and thousands of short replies would bury the signal. Posts and comments get the same cut, so the two lines on the chart stay comparable. How we picked the subreddits is in the method section.

ChatGPT became public on November 30, 2022. In that quarter, 0.83% of long posts in our sample had an em dash, about where the share had been all year. Over the next 18 months it crept up to 1.19%.

The jump came in August 2024. In July, 1.28% of long posts had an em dash; in August, 1.95%; by December, 3.12%. In July 2025 it reached 6.83%, the highest month in more than ten years of data. By quarter, the peak is Q2 2025 at 6.53%, 9.4 times the level of early 2021.

We can't tie the August jump to any particular release, and timing is all this data shows: it came three months after OpenAI released GPT-4o and about 20 months after ChatGPT launched. Most of the rise happened in the twelve months that followed.

Reddit comments are mostly typed straight into the comment box, on the same phones and keyboards people use for posts. If a keyboard or an app had started inserting em dashes on its own, comments would show it too.

Comments did rise. Between Q2 2024 and Q2 2025 the share of long comments with an em dash went from 0.65% to 1.32%, a gain of 0.67 percentage points. Long posts gained 5.35 points over the same year, going from 1.19% to 6.53%. Since then comments have stayed between 1.10% and 1.24%.

Posts are where people paste in text they wrote somewhere else: a story drafted in a notes app, a launch announcement cleaned up in a chatbot. That's the most likely reason the two lines split, though it's an inference from the pattern and not something we can observe.

Autocorrect is the usual objection, and it has changed Reddit's punctuation once already. In September 2017 Apple shipped iOS 11 with Smart Punctuation turned on by default, which converts two typed hyphens into an em dash. Daring Fireball was already complaining about it during the beta.

Our data picks it up. Between Q3 2017 and Q2 2018 the em dash share rose by 0.24 percentage points in posts and 0.18 in comments, while the double hyphen, the old way to type a dash, fell in both. When the keyboard changes, both kinds of text move together.

The 2024 rise looks different. Double hyphens in posts were at 0.40% in Q2 2024 and 0.40% a year later, and comments gained 0.67 points against 5.35 for posts.

Two jumps compared: em dashes and typed double hyphens (--) in long posts and comments

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Two jumps compared: em dashes and typed double hyphens (--) in long posts and commentsPeriodEm dash, postsEm dash, commentsDouble hyphen, postsDouble hyphen, commentsQ3 2017 → Q2 2018 (iOS 11)0.29% → 0.53%0.52% → 0.70%1.17% → 0.76%1.14% → 0.78%Q2 2024 → Q2 20251.19% → 6.53%0.65% → 1.32%0.40% → 0.40%0.39% → 0.36%Double hyphen = " -- " with spaces, or two hyphens between letters. Share of long posts or long comments that contain it.

A big change in a few busy subreddits could draw a curve like this by itself, so we checked subreddit by subreddit. 72 subreddits in the sample had at least 300 long posts both in 2021 and in 2026. The em dash share in posts went up in all 72 and at least tripled in 60. For comments we used the 81 subreddits with at least 3,000 long comments in both years: the share went up in 78 but tripled in only 28.

In the median subreddit, 0.50% of long posts had an em dash in 2021 and 4.00% in 2026. For comments the median went from 0.42% to 0.81%. In 67 of the 69 subreddits that pass both thresholds, posts gained more than comments. Taken together, the 72 subreddits give almost the same quarterly curve as the full sample: 0.69% in Q1 2021, 6.49% in Q2 2025 and 5.71% in Q3 2026.

A few communities stand out. In r/SideProject, where people announce things they've built, 29.3% of long posts in 2026 contain an em dash, up from 2.0% in 2021. r/writers started high, as you'd expect from people who care about punctuation, and still went from 2.7% to 13.8%.

Subreddits with the highest share of long posts containing an em dash, 2026

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Subreddits with the highest share of long posts containing an em dash, 2026SubredditLong posts, 2026With an em dashSame, 2021r/SideProject59,09529.3%2.0%r/writers17,92213.8%2.7%r/sportsbetting3,85612.8%0.2%r/IndieDev7,26911.8%0.9%r/NoFilterNews1,6279.8%under 0.1%r/referralcodes28,5389.4%1.6%r/Christianity60,2818.6%3.1%r/R4R30Plus18,6788.3%1.2%r/delhi23,7958.2%0.3%r/AskIndianWomen27,6937.6%n/aJanuary to September 2026, among the 100 subreddits in the sample with at least 1,000 long posts in that period. The 2021 share is shown where the subreddit had at least 300 long posts that year. All 100 subreddits as CSV.

For years almost nobody on Reddit talked about em dashes. In these 100 subreddits, between 12 and 69 comments a quarter used the words "em dash" from 2016 through September 2024. Then came 127 in Q4 2024, 320 in Q1 2025 and 2,575 in Q2 2025. Per million comments, the count went from about 2 in mid 2024 to 83.

Same 100 subreddits. Case-insensitive match. Source: KissMyPost analysis of public Reddit posts and comments.

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What happened after the July 2025 peak

By month, the peak came in July 2025, when 6.83% of long posts had an em dash. In August the share fell to 5.70%, 17% lower in a single month, and in December 2025 it reached 4.78%. Long comments fell over the same step, from 1.31% in July to 1.04% in August.

August 2025 is the month GPT-5 became ChatGPT's default model, taking over from GPT-4o. In mid-November, OpenAI's CEO said ChatGPT now follows custom instructions to leave out em dashes, and the following month was the lowest since the peak. That's the order of events. This data can't show that either change caused the drop.

The fall wasn't limited to a few busy communities. Of the 74 subreddits with at least 300 long posts in July 2025 (5 or more of them with an em dash), 63 had a lower em dash share in August, and the median one dropped to 0.82 of its July level. It doesn't look like a summer dip either: from 2016 to 2024, the July to August change in posts ranged from 8% down to 52% up.

The em dash jokes don't explain it on their own, at least not by timing. Comments that mention em dashes peaked in May 2025 (1,168 that month), while the share in posts kept climbing into June and held there in July.

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Share of long Reddit posts and comments with an em dash, by month, January 2024 to September 2026Posts: 1.28% in July 2024, 1.95% in August 2024, 6.83% at the peak in July 2025, 5.70% in August 2025, 4.78% in December 2025, 5.61% in September 2026. Comments: 0.72%, 0.82%, 1.31%, 1.04%, 1.09% and 1.11% in the same months. October 2025 is left out.1%2%3%4%5%6%7%Jan 2024Jan 2025Jan 2026GPT-4oMay 2024GPT-5Aug 20256.8%5.7%CommentsPosts

Same 100 subreddits. October 2025 is left out because that month's data looks wrong (see the limits below). Source: KissMyPost analysis of public Reddit posts and comments.

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Other big monthly drops, and what shipped that month

The table lists the four largest month-to-month drops since the peak, next to what changed in ChatGPT around the same time. Most of them line up with a release, but that is weaker evidence than it looks: OpenAI shipped something new in most months of this period, and GPT-5.4 came out in March 2026, a month when the share went up. Only August 2025 really stands out. It's the biggest drop, it came in the month the default model changed, and no July to August change in the nine years before it comes close.

Largest monthly drops in the share of long posts with an em dash since July 2025

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Largest monthly drops in the share of long posts with an em dash since July 2025MonthShare of long postsChangeWhat changed in ChatGPTAugust 20256.83% → 5.70%-17%GPT-5 becomes the default model (Aug 7)December 20255.56% → 4.78%-14%GPT-5.1 (Nov 12) and the no-em-dash fix (Nov 14), then GPT-5.2 (Dec 11)May 20266.26% → 5.64%-10%GPT-5.5 Instant becomes the default model (May 5)June 20265.64% → 5.09%-10%Month after GPT-5.5 Instant became the defaultChange against the previous month; October 2025 is left out, so November 2025 is compared with September. Release dates: GPT-5, GPT-5.1, GPT-5.2, no-em-dash instructions, GPT-5.5 Instant. April 2025's rise of 39%, the second largest before the peak, came after a GPT-4o update on March 27, 2025.

In 2026 the monthly share has stayed between 5.09% and 6.26%, still seven to nine times the early 2021 level. Em dashes in titles kept growing: in Q2 2024, 0.12% of long posts had one in the title; by Q2 2025 it was 1.00%, and in Q3 2026 1.22%.

This part uses a wider set: the full list of 400 subreddits our sample was drawn from, and their long text posts from 2019 to September 2026. For each post we know whether it made the top 10% of its subreddit that month by our engagement score. The top 10% is measured against every post in the subreddit, links and images included, so long text posts land there less than 10% of the time. We compared how often posts with an em dash made it against how often you'd expect, given the subreddit and the month. A ratio of 1 means no difference.

From 2019 to 2021, posts with an em dash did better. They reached the top 10% 1.44 times as often as expected for their subreddit and month. In raw numbers, 11.9% of them made it, against 7.5% of long posts