LinkedIn longform posts are 41 percent AI-generated, while X stands at roughly 33 percent
New data from Pangram confirms that a large portion of the written content users encounter on major social platforms is machine-written. The study found that 41 percent of longform posts on LinkedIn are fully AI-generated. On X, roughly a third of longer articles are AI-generated. About one in ten longer posts on Reddit and Substack are also AI-written, according to the findings.
Pangram collected this information using a Chrome extension that scans text in the background. The tool determines whether a post is likely AI-generated or human-written. Because the software runs passively, it only records content that users actually see while browsing. This method answers a specific question: is the internet actually being poisoned with low-quality AI text, or is that content hidden away on obscure sites that no one reads? The answer is clear. Humans are regularly wading through machine-generated slop on hugely popular websites.
“This isn’t something that had really been studied before—how much AI content people are actually seeing,” Max Spero, the CEO of Pangram, said in a phone interview. “AI content is a tax on readers’ time.”
The research relied on users opting in to share their browsing results. Pangram analyzed roughly a million posts that users scrolled through on LinkedIn, Medium, X, Reddit, and Substack over a two-month period. The company split the content into “shortform” (between 50 and 250 words) and “longform” (longer than 250 words). The data suggests that longer posts are more likely to be AI-generated than shorter ones.
Forty percent of longform LinkedIn posts analyzed were fully AI-written. A quarter of X articles were fully AI written, but another 23 percent of X articles were AI-assisted, meaning they were drafted, edited, or rewritten by AI with some human elements. It makes intuitive sense that longer form content is more likely to be AI-generated because people usually do not bother to generate a few-word response or a pithy comment. 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. In an earlier article, I wrote about the cognitive weight of constantly assessing whether a piece of writing is AI-generated. After writing that piece, I decided to try the extension to see whether its assessments aligned with my own. After using it for nearly two months, my experience largely aligned with Pangram’s data. Many of the longform articles I see on X are obviously AI generated and detected as such. A huge amount of the LinkedIn posts I see are obviously AI-generated.
Because the study worked by passively detecting content people see in their normal browsing, the data is potentially more useful than other studies that estimated the raw percentage of AI-generated content on the internet. Prior studies found that as many as a third of new sites are AI-generated, but they allowed for the possibility that the content was flooding the internet while remaining of such 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 had for years built AI writing tools into its platform, making it incredibly easy to post AI-generated content. 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 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 and false negatives. 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.
What it means
The shift from short comments to long-form AI text changes the daily experience for workers and readers. On LinkedIn, professionals are now forced to read machine-written summaries that offer little unique insight. On X, the new article format has become a primary vector for low-quality content, overwhelming users with verbose text that lacks human nuance. The data suggests that people are comfortable letting AI speak for them in professional settings, but the result is a feed where genuine human perspective is harder to find.
