A Third of the Post-ChatGPT Web Is AI-Written, Pew Finds

AI-written content is everywhere, literally.

One in 10 English-language webpages now shows significant signs of being written by AI, according to a Pew Research Center study published Thursday. Narrow that sample to only pages published since ChatGPT launched in November 2022, and the share jumps to 35%.

The findings come after researchers pulled roughly 490,000 pages from the Common Crawl web archive, spanning January 2021 through July 2026, then ran the text through Open Pangram, an AI detection model.

The AI fingerprint isn't spread evenly. Pages on .com domains show signs of AI authorship at roughly 10 times the rate of .edu or .gov domains, which sit near 1% each, and about double the 4.6% rate on .org sites.

In 2021, all four domain types looked nearly identical.

How Pew spotted the machines

The detector doesn't flag any single word or phrase but instead weighs statistical patterns across large batches of text. But some individual tells have become sharply more common since 2023: The usual suspects, em dashes (much as we like them ourselves) now appear roughly twice as often, Oxford commas are up 63%, and AI-favored words like "delve," "interplay," and "testament" have more than doubled in frequency.

"Negative parallelism"—constructions like "it's not just X, it's Y"—has nearly tripled since 2023, though Pew notes it's still rare overall. Decrypt has tracked these same tells before, and Merriam-Webster made it official in December, naming "slop" its word of the year.

Pew is careful to note the limits here: detection models can misclassify individual pages in both directions, and "significant signs of AI authorship" doesn't mean a page was written entirely by a machine—plenty of the text was likely AI-assisted rather than AI-generated outright.

Open Pangram comes from Pangram Labs, whose detector has also turned up in separate research finding AI-generated text in roughly 9% of U.S. newspaper articles this year, including opinion pages at outlets like The New York Times.

That said, AI detection may become an easier task with time, not because of patterns but because of the underlying technology. Big AI companies like Anthropic are already working on model-level text fingerprint, which would make AI text easy to identify while minimizing errors.

The domain gap tracks who's publishing and why. Academic and government sites run through editorial review, institutional sign-off, and slower publishing cycles; .com domains include everything from newsrooms to affiliate-marketing content farms churning out pages at a pace no human editor could sustain.

At scale, the trend line is steep regardless: The .com AI-authorship rate climbed from roughly 1% in January 2021 to 9.35% five years later, in January 2026 alone.