If I had to mentally recreate places, I think the older spaces of IRC would be akin to a village; not huge, but everyone tended to be tight-knit and fairly close
Discord (and Mastodon to a lesser degree) feels more like a bunch of large skyscrapers, but they're almost all empty and lifeless
I guess one way to explain it more is just that IRC had much fewer channels (usually one for a community, sometimes two or three) but with Discord you have many different servers and they all have a huge collection of channels.
@GeekDaddy "seems like" \:|