@silverpill @grishka This is true, but you would see the result of an algorithm applied to the subset of Fediverse posts that the relay applies to. If a relay were to subscribe to a large number of other relays and servers and effectively cover the Fediverse, would it end up as resource-hungry as Bluesky? I suspect the resource requirements for three AT protocol are because of the design decision to act like non-frderated systems, where if an algorithm boosts your post it is boosted for everyone with similar interests.
I can see the possibility of topic based relays in a federated environment. These relays would have to be able to say to other relays and instances "give me everything related to Chipmunks" or whatever, and collect a smaller stream of relevant posts from a larger number of sources. This might be more scalable.