Uh.. that's unfortunate because many will just interpret it as federation being bad
IRC networks sometimes split. That didn't mean that they didn't generally stay together. Just that there were several major networks and a some isolated servers.
Usenet, as far as I know, generally remained one network, but occasionally saw Usenet Death Penalties.
XMPP supports federation, but organization, like businesses, exist that choose to use isolated XMPP servers.
discodoubloon