Do At-Proto Users Know This Is Public?

The AT Protocol’s personal data servers make information created by connected apps publicly accessible, and users may not realize how easily it can be inspected or collected. While exploring the ecosystem, the writer checked Skyreader, an RSS reader, and found that its subscription records include users’ feed URLs alongside their account identities. By looking up people who had reviewed the app, the writer could see what feeds they followed - and discovered private, paid, and members-only feeds, including Club MacStories, 404 Media, Patreon, and GitLab feeds. A feed URL can provide access to content that subscribers may have assumed was private, while also revealing their interests.

The exposure is not limited to individual browsing. The writer queried a Bluesky relay, identified the users’ data servers, and retrieved more than 1,300 Skyreader subscription records without authentication or meaningful restrictions. Other AT Protocol apps raise similar concerns: some Discord-like services publish all messages, and a Twitch-like service makes chats searchable. The central concern is a mismatch between the protocol’s openness and users’ expectations. Public availability may be intentional, but that does not mean people understand the consequences of connecting apps or storing sensitive activity in public records. The examples show that data can be both easy to find and useful for uncovering information users would not knowingly disclose.