More than a third of new web pages are now written with artificial intelligence, according to research from the Pew Research Center, adding to concerns about the "dead internet theory".

The study finds 35 per cent of web pages published since ChatGPT's launch show "significant signs of AI editing or authorship".

Across a broader five-year sample, that figure drops to 10 per cent, reports The Independent.

Researchers built an archive of nearly half a million English-language web pages and ran them through Open Pangram, a tool that detects machine-generated text.

The findings come weeks after Cloudflare revealed AI bots now generate more internet traffic than humans, a first.

The "dead internet theory" holds that much of the web is now both produced and consumed by automated systems rather than people.

Pew notes that AI-detection tools have limits and can misclassify text either way, but it says a large sample helps offset individual errors and shows a reliable trend.

The study also tracks writing quirks tied to AI. Em dashes have roughly doubled, Oxford commas are up 63 per cent, and words like "delve" and "interplay" have more than doubled in use.

Such quirks can appear in human writing too, researchers say, but broader statistical signals point to the same trend.

AI content also varies by domain. Pages on .com sites are about twice as likely to show AI authorship as .org sites, and roughly ten times more likely than .edu or .gov pages.