Since there is no face-to-face contact in a MOO, it is sometimes confusing to figure out who is speaking to whom. A player can page another one privately, anywhere else on the moo.

You sense that Infrared_Guest is looking for you in The Living Room.
It pages, "hello there."

Or a player can whisper to another one in the same room, again privately.

Infrared_Guest whispers, "hello there"

Or a player can just address another one in the room, publicly.

Infrared_Guest [to troz]: hello there

Regardless of how these exchanges take place, just as in real life, the world keeps moving. Other conversations that are occuring in the room continue to be seen and players can still interact and interrupt, if they want.