> Sure you have a lot of servers, but they all run the same software and approach the problem in the same way.
The 'servers' are simply endpoints within a federated network. You can have a frontend "app" interoperate with those endpoints while exposing a different UX, perhaps one that's more old-school BBS- or forum-like.
Or you can have endpoints that expose a slightly diverging logic, perhaps building on other web standards (such as WebMention) for their analogs of the BBS-like "reply", "topic", "thread" etc. But since these are all part of one Fediverse, interoperability across endpoints will be preserved.
> What I'd most of all like is something that lets the visitors own their own posts while still allowing some form of communication.
This can happen if the visitor owns a server and makes their posts available from there via Fediverse standards. The posts can then either be federated directly (if allowed), or "mentioned" (like a trackback) on other servers.
ActivityStreams is the "RSS" like standard in the Fediverse, which can be implemented entirely statically, with no "active" server-side logic whatsoever. ActivityPub is the active "push" part of the standard, which enables "post" workflows from users; the server itself can also use ActivityPub to "push" its content to a federated endpoint in the network, which removes any propagation delays introduced by polling.