Consumers are tired of scrolling past content they suspect was never written by a person, and on LinkedIn, that suspicion is often correct.
More than 40% of LinkedIn posts longer than 250 words are fully artificial intelligence-generated, according to AI detection company Pangram. The company looked at more than 1 million posts across LinkedIn, Medium, Reddit, Substack and social platform X. It found that LinkedIn had the most long-form AI content.
Substack had one of the lowest rates of any platform for long-form content, with roughly 20% of its posts flagged as AI-generated or AI-assisted, Pangram said. Reddit’s overall rate looked even lower, just 4.4% combined, but that number is misleading. It’s driven almost entirely by Reddit’s replies, which were 98.1% human-written and made up most of what Pangram scanned on the platform. Reddit’s own top-level posts, the ones actually comparable to a LinkedIn post or a Substack piece, were AI-generated at a similar rate to X.
Platforms are racing to fight back against the AI slop.
Substack launched an AI detection feature on July 21 built with Pangram, letting readers scan any post, note, comment or reply of more than 100 words published on or after that date to see an estimated split between human-written and AI-generated text, according to a July 21 company blog post written by Substack CEO Chris Best.
LinkedIn followed Thursday (July 30), with LinkedIn Chief Product Officer Hari Srinivasan announcing a “Seems like AI slop” reporting button, accessible from the three-dot menu on a post.
“We are ramping up a series of new and improved classifiers that identify if a post is AI-slop or generally low-quality content,” Srinivasan said in a Thursday LinkedIn post. “This will reduce the amount of AI slop you might see in suggested content and content from outside your network.”
LinkedIn Is Asking Users to Flag AI Slop Themselves
LinkedIn is attempting to ensure that when users visit the platform, they connect with real people and share real perspectives, Srinivasan said in the post. The company blocks hundreds of thousands of automated comment attempts daily.
“AI slop is a top priority for all of us,” he said in the post. “We really care about this.”
Every report becomes training data for classifiers, reducing how often flagged content appears in posts suggested to people outside a poster’s existing network.
LinkedIn is also retiring its own “Enhance your post” AI writing tool for a more conservative proofreading feature that preserves a user’s original voice, Srinivasan said in the post. The company will privately notify users when their content reads as inauthentic due to heavy AI use.
Substack put the detection tool in the reader’s hands rather than routing everything through moderation. Readers scan a post and see a percentage breakdown; creators can add a “How I make this” disclosure, disable detection on individual posts, or dispute a result, according to Substack’s support documentation.
In the July 21 blog post, CEO Best framed the launch around the specific fear that Substack could drift toward what LinkedIn had become.
“When content made by no one takes over parts of the internet that are supposed to be human, it pollutes the commons and makes it hard to discover and hear human voices,” he said.
A Flawed Detector Is Still Better Than No Detector
Neither company claimed certainty. Pangram’s scores are estimates based on stylistic patterns, not proof of how text was produced. Independent researchers found that some AI-generated text can read as human to detectors.
The business logic is more straightforward than the detection technology. A social platform’s product is attention; a newsletter platform’s product is subscriber trust. Both erode when readers cannot tell a human voice from a mass-produced one.
Online news aggregator Digg shut down its Reddit-competitor product in March, citing an inability to keep pace with bot-driven content, The Verge reported March 13.
Meanwhile, Cloudflare has said automated bot traffic on the web now exceeds human traffic, a threshold it reached earlier than forecast, NBC News reported in June.
LinkedIn and Substack are betting that the platforms that survive the next phase of generative AI will be the ones that can prove a real person is still on the other side of the post.
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