On Saturday somebody on Reddit typed one line into Google - site:claude.ai/share - and up came a list of conversations people believed they were sharing only with a colleague or a friend. Medical reports on real patients. Clinical trial results with names attached. Names and phone numbers of primary school children. Internal documents marked internal. Employee appraisals with personal data.

The feature that made this possible is ordinary and sits in almost every tool of this kind: you create a link to the conversation and „anyone with the link can view it”. That is the wording. The problem is that with Google Docs the same sentence does not mean the document will show up in search results - and here it did.

Anthropic's response is worth reading twice, because the weight of it was pushed back onto the user. The company explained that links appear in search results only if somebody posted them somewhere search engines look - a forum, a social network. A link sent privately, they say, stays out of it.

„We give people control over whether they publicly share their conversations and, consistent with our privacy principles, we do not share site directories or maps with search engines like Google,” said spokesperson Amy Rotherham. „When someone shares a conversation, they are making that content publicly available and, like any other public web content, it can be archived by third parties.”

Technically - correct. Practically - how many users clicking „share” understand that this means the public web? When one sentence in an interface can mean both „show it to a colleague” and „publish it on the internet”, and the difference is paid for by the person who sent a medical report, the problem is not with the reader of the instructions.

Google, of course, stands to one side. „Neither Google nor any other search engine controls which pages are published publicly on the web, and these pages were indexed across multiple search engines,” said spokesman Ned Adriance. Everyone holds their half of the fence, and the data went through the gap between them.

This is not the first time. Last year Forbes reported a similar case involving hundreds of indexed conversations - Google estimated it had indexed just under 600 before the pages disappeared. That same year a researcher managed to collect around 100,000 publicly shared ChatGPT conversations. So the pattern is familiar to both the companies and the journalists; it happened again anyway.

By Monday afternoon the same search no longer returned results, which suggests the hole has been closed. But a closed hole does not retrieve the data somebody has already seen or saved. If you have shared a conversation by link, it is worth checking: Settings, then Privacy, then Shared Chats. That is all the user can do - and that is precisely the point.