@helge @smallcircles All this talk of a model of different item types interacting just reminded me that a few years ago, long before I even knew the fediverse existed, I wrote out my idea for a social network. In hindsight, it's funny how close it is to the fediverse data model, actually.
Sharing here in case you find it interesting, though I'm afraid it's screenshots because Mastodon doesn't allow sharing documents as attachments (hey, 'document' could be an item type!):