Yes it says Fediverse. They probably do mean microblogs, where at least it’s a real phenomenon. It could also apply to stuff like Pixelfed.

In the threadiverse, you’re posting in a community, not your profile. It’s on the community to downvote unwanted comments and on mods to remove rulebreakers. In a rare post an OP doesn’t want any advice, like sharing art or a personal story, unless it’s a written rule of the community it’s on the OP to explicitly say so.

Yeah I’ve heard this too. Both iOS and Android hide their file structure. But besides that most things are done online without files.
So people who learn mobile or websites before computers use it less.

You can chat on different servers, so I’d say it’s federated.