LinkedIn is the undisputed king of long-form AI slop, according to a study spanning five platforms

One in four social media posts over 250 words is AI-generated, according to a Pangram analysis. LinkedIn tops the list with 41 percent of long-form posts flagged as AI-written. The platform made up only a third of all posts scanned but accounted for nearly two-thirds of all detected AI content. On X/Twitter, close to half of long-form articles were AI-generated or AI-assisted. Substack had the lowest long-form AI rate at around 10 percent. Reddit replies were 98 percent human-written, but standalone posts contained AI text far more often.

The data comes from Pangram’s Chrome extension, which scanned over one million posts across five platforms between April and June 2026. The company claims its Pangram 3 detection model has a false positive rate of 0.01 percent, but it’s likely better at identifying human-written content than AI-generated content, so the real AI rate could be even higher. The study makes no claims about content quality, but LinkedIn itself seems to feel the pressure and has already started cracking down on AI-generated posts.