@timbray
The idea is very old and very good at the same time.

But as far as I know, some people consider even not ActivityPub projects a part of the Fediverse.
The "Fediverse" term itself sounds somewhat ambiguous, so it's not very illogical for them to do so.

I'd suggest to stick to "ap" or "activitypub" schema unless you're planning to propose something as universal as "magnet" which could work for BitTorrent and other protocols at the same time.