I think the terminology you're looking for is "homeserver." Homeservers are tied to a single hostname / domain, but may be a collective of servers running the d

I think the terminology you're looking for is "homeserver." Homeservers are tied to a single hostname / domain, but may be a collective of servers running the different services that comprise the protocol itself. That said, you _do_ have to worry about spam from other homeservers, but that only matters if you have users from that other homeserver in your room. You can choose to federate / not-federate on a room-by-room basis, or just not federate at all ever. Needless to say, you're right that it is a bit different than IRC in that regard (IRC can just kline hosts / IP ranges from the whole service if you're spamming). However, in practice there's a lot less instances of random spam such as in the article than you would think. For myself, I never noticed any of these spammers at all (anectodal, so mileage may vary). I do have my own homeserver through Element Matrix Services, but I am part of a good number of rooms that exist purely on the Matrix.org server. Certainly I have to "police my users," but that's pretty easy since I run a small homeserver for ~5 users, and we just federate with the greater network when needed. I guess I agree with you in general that there's different failure modes, but I don't think it's as simple as dismissing matrix because it "has the same spam problem as email" compared to IRC. In practice at least, it doesn't seem to be as much of a problem despite how much larger than IRC Matrix has become.