Usenet never really went away, it just got quieter in favor of easier to use options. I still use it pretty frequently for the couple of things is really good for.

It's a gross oversimplification, but think of usenet as a kind of early social media or proto-forums. Before websites, facebook, or anything resembling the modern internet took off, news groups were howl ike-minded people connected. You could post articles to various groups, sort of like a dead drop, and that post would be related around to all of the various providers based on who subscribed to whom. The user interface was very similar to an email client and you could look at it like sending email to a global address (with no user@ part)

The structure of usenet was based on dot syntax, with the topic scope becoming progressively more narrow as you went along. You would have things like: alt.books.scifi

alt.books.scifi.authors

alt.books.scifi.authors.asimov

or comp.software

comp.software.unix

comp.software.unix.compilers

with each of those groups focusing on more specific topics as they went down the hierarchy, and thousands of groups and subgroups.

Usenet was one of the first federated services, too. Due to how replication was managed, no one single server or host controlled it. Your server could go down, but any other server that replicated (federated) with your instance would have all the same articles unless they were marked as a "local only" group.

This is all very early in the internet, but i feel like this is the kind of thing that will save us in the end. Federated services, newsgroups, personal websites, and forums can free us from the shackles of Corp owned platforms. It's amazing how relevant it still is for a technology spun up in the early 80s. Wikipedia has a great article on usenet that everyone on a fediverse platform should read to help understand how we got here and how quirky and weird and fun the old internet used to be (and hopefully can be again)

"If Lemmy and Mastodon were playing football, usenet would be the stadium that they played on. It would be the sun that shone down on them."

-- Nancy, The Craft

Picture Lemmy, where anyone can create and subscribe to communities about whatever, only without the multimedia or link posts. Everything, at least in the beginning, was strictly text-based posts and threaded replies.

(Ways to attach binary files such as images were hacked in by converting the binary data to text. That's still how email attaches files today, though it's all behind the scenes and not obvious to average users anymore.)

Worse in every way but you could use it to steal media. Like an even more angry and nerdy Lemmy.