Over 780 websites now serve llms.txt files, the proposed standard that tells AI systems what to pay attention to on a site. The adopter profile is strikingly narrow: developer-facing companies with API documentation. Cloudflare, Vercel, Stripe, Coinbase. Not retailers, not media companies, not banks.
Then there's Google. Its search team publicly compared llms.txt to the abandoned keywords meta tag. In December 2025, someone spotted Google had quietly added the file to its own Search Central docs. Hours later, it vanished. A spokesperson offered only a cryptic emoji.
The pattern worth watching here is the shape of adoption, not the number.