Scene from 1994
You connect from a terminal, from a university lab, the only place where you have internet access, to your #unix server.
You type finger <user> to see if a friend/colleague/professor it's on line on the nearby room.
You see that he last typed on a terminal few minutes ago, so it's probably there, so you decide to

ytalk <user>

and have a chat.
Hey, but those command works as well if you use <user@some other university> !

Whoa, this thing is interconnected, it's federated !