there may well still be value in a site being able to tell other services that it has new content that’s been updated.
The lost infrastructure of social media.
Anil Dash

Site feeds, PubSubHubbub, Salmon, Activity Streams, etc., are all efforts in this direction, and adding in versioning to track changes and the addition of blockchain based attestation of timestamps and provenance may make them valuable enough to implement and catch on.