41% of long LinkedIn posts are AI-generated, browsing data shows

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A shocking amount of the content that users encounter on popular social media websites is likely AI generated, according to data from a company that detects AI writing. As much as 41 percent of longform written content seen by users on LinkedIn is likely to be fully AI-generated and roughly a third of longer posts on X are AI-generated; roughly one-in-ten longer Reddit and Substack posts are AI, according to the data .

The data was collected using a Chrome extension from Pangram, a company that detects AI-generated writing. Pangram’s Chrome extension scans writing that users encounter while browsing and determines if any given post is likely AI-generated or likely human written. Because Pangram works passively in the background while a user is browsing the internet, it only scans posts that its users actually see. This helps answer the question of whether AI slop is actually poisoning the internet that humans actually use, versus polluting the internet more broadly. The answer is unequivocal: AI slop writing is not just sequestered off on unpopular automated SEO farms or spam sites that no one reads; humans are regularly wading through AI dreck on hugely popular sites.

“This isn’t something that had really been studied before—how much AI content people are actually seeing,” Max Spero, the CEO of Pangram, told me in a phone interview. “AI content is a tax on readers’ time.”

(Pangram formerly advertised on 404 Media. I am covering this data because I have written many articles about how AI-generated content is taking over social media and is brute forcing social media algorithms , and I have not seen other data that attempts to measure the actual popularity of slop.)

For this research, Pangram specifically asked users of its Chrome extension to opt-in to share Pangram browsing results with the company. The company analyzed roughly a million posts that its users organically scroll through across LinkedIn, Medium, X, Reddit, and Substack over a two-month period. Pangram found that, universally, longer posts on all platforms are more likely to be AI-generated than shorter posts. The company split the content it analyzed into “shortform” (between 50 and 250 words) and “longform” (longer than 250 words).

The data suggests, perhaps unsurprisingly, that a huge portion of longform posts on LinkedIn and X’s new article format are fully AI-generated or AI-assisted (meaning drafted, edited, or rewritten by AI with some human elements). Forty percent of longform LinkedIn posts analyzed in the data were fully AI-written; a quarter of X articles were fully AI written, but another 23 percent of X articles were AI-assisted, the company said. It intuitively makes sense that longer form content is more likely to be AI-generated, because people usually won’t bother to AI-generate a few word response or a pithy comment on a quote tweet, for example. AI is also famously verbose , meaning AI-generated content is more likely to show up in longer posts.

“Our data shows that AI-generated content is a problem across all platforms, and it is hitting longform content especially hard,” the company wrote in a blog post. “Contrary to what one might expect, people are overwhelmingly willing to use AI to speak on their behalf in professional settings that are associated with their real identity, and less likely to use it on casual and anonymous platforms.”

The study also found that top-level posts on LinkedIn and Reddit are far more likely to be AI-generated than the comments underneath an original post.

I have been using the Pangram Chrome extension for several months now, after interviewing Spero for an article I wrote called “ Your AI Use Is Breaking My Brain .” In that article, I wrote about the cognitive weight of the constant assessments I am doing when I’m browsing the internet, trying to determine whether a piece of writing is AI-generated or not. After writing that article, I decided to try the Pangram Chrome extension to see whether its assessments of likely AI-generated writing aligned with my own brain’s assessments. After using the extension for nearly two months, my experience has largely aligned with what Pangram’s data suggests: Many of the longform articles I see on X are obviously AI generated, and are detected by Pangram as such. A huge amount of the LinkedIn posts I see are obviously AI-generated.

Because of the way the study worked, by passively detecting AI generated content that people see in their normal browsing, the data is potentially more useful than other studies that have sought to estimate the raw percentage of AI-generated content on the internet, but not whether anyone was actually seeing that content. These prior studies, which found that as many as a third of new sites are AI , allowed for the possibility that AI-generated content was flooding the internet but that it was of such a low quality that actual people may not have been seeing it.

The Pangram data raises questions about what platforms are doing to promote or disincentivize AI slop. LinkedIn, for example, had for years built AI writing tools into its platform meaning that it has been incredibly easy to post AI-generated content on the platform and that AI-generated content became incredibly common on the platform. In May, the company announced that it is trying to disincentivize AI content in the name of “keeping conversations real,” and the AI writing assistant is no longer built into the post button. Reddit, meanwhile, has become a vector for companies trying to game LLM tools by promoting their products on the site because AI search tools often scrape Reddit. But Reddit’s moderators are also overwhelmingly anti AI, and the company has worked to delete AI-generated posts and ban accounts that spam. On Monday, Reddit published a blog post saying that “in the age of AI, spam, bot activity, and inauthentic content are top of mind for people who love Reddit (and humans).” In the last few weeks, Reddit launched an ad campaign called “people are best” specifically highlighting that its users are human. A Reddit spokesperson referred us to the blog post when asked for comment.

As we have reported before, no AI detector is 100 percent foolproof , and Pangram certainly has both false positives (human content detected as AI) and false negatives (AI content detected as human). Spero said that the company is constantly working on minimizing both, and that it estimates its false positive rate at roughly one in 10,000. He said he believes the Pangram data is likely a “lower bound” and that the actual problem is likely worse, because people who are willing to install AI detectors on their browsers are likely trying to avoid AI-generated content.

“I think the data generalizes out [to non Pangram users], but that it’s a lower bound on AI content because someone with the Pangram extension probably cares more about seeing AI content than the average person and would be more likely to block or mute AI posters,” he said.

A LinkedIn spokesperson told 404 Media in a statement that “Professionals come to LinkedIn to hear from real people and their unique insights and perspectives. We actively work to reduce low quality, automated or generic content, and while AI can be used to beat the blank page problem, our focus is on surfacing professional conversations that help people advance their careers.”

Substack and X did not respond to a request for comment.