Earlier quoted context omitted.
https://en.wikipedia.org/wiki/Network_News_Transfer_Protocol Originally over UUCP (Unix Unix Copy Protocol) and done via dial ups at night (when the rest of the batch transfers were done - email too with the old bang path). The two servers would exchange all the batched email and news posts that were routed to the other side. RFC 977 ( https://www.w3.org/Protocols/rfc977/rfc977 ) has an example of how files are copie…
But how did all of this line up within the federated or not conversation? If each ISP could host their own version, that doesn't sound federated. But who was in control of the "main" source of truth type of version?
http://usenet.trigofacile.com/hierarchies/index.py?status=pr... and https://web.archive.org/web/20220815151921/http://bofh.taron...
Sure, an ISP could host its own news.answers site and not accept posts from others for that group nor pass messages from it out to others... but that would be a rather lonely place.
Likewise, one ISP may have a different set of posts that it shows for a news group because of moderation actions (we don't accept any posts greater than 1MB in size because of disk space issues and we don't host any newsgroup named *.binaries).
Federation comes from exchanging those posts using a common protocol - NNTP.