I’ve seen some active instances die due to admin neglect (not paying the bills, for instance), and I’ve wondered how those communities have fared since, since they’d have to start over elsewhere, and without all the content and history from their origin server. Same goes with user accounts too.
Just read a thing about how persistent usernames may work better than actual ID. Of course, I don’t have a link, and I’m not finding anything on Google right now, but as someone who uses the same handle across multiple services, which makes my activity traceable, but not necessarily to my real identity, I definitely think there’s something to that.
Served as “flat files” - filesystem, object store, what have you. No server logic generating content, just passing around of strings and binary data. Files are the representation are the source of truth. Counter to a web app, where the content response is ephemeral and the “source of truth” is scattered across a writeable DB and recombinated (potentially) on every request.
Interesting question though, I (a web dev) just take the term for granted.