

I don’t feel something like crowdsourced tagging would work for the Fediverse unless it has some sort of approval system built for either post’s author or commuity admins (and those are already busy). Otherwise it would be far too easy to do things like brigading, or pushing government-style “self-censorship” (or straight out censorship of others: just get an army of bots “volunteers” into one instance, let the resulting blocks federate). Something closer to AO3 style tagging, where the author retains most control but readers can add tags to things that are valid only to them (and maybe to people they share data with too?) should workbetter IMO.
Blocking keywords is not reliable to block topics because a keyword does not a topic make, for example in this post I mention queer, socialism, musk and islam yet it’s not topical to any of those things.


What for?
XMPP is quite robust and open, and while it’s not in the level of simplicity of, say, IRC, it still beats pretty much everything else on connectivity and efficiency, and can be run on a potato. Storage is only slighly a concern.
OTOH nu-protocols like Mastodon stuff or Matrix stuff, while they are nice to have, are notoriously badly designed because kiddies these days can’t bother to learn C. This results in highly energy-, memory- and storage-consuming systems. In the amount of RAM I need to kick up a Matrix server (assuming it even runs) I can run ~18 XMPP services and about ~240 ircd services.