In a desktop session, subscribe to the one-liner demo channel and notice a new "chat" notebook window.
listener = ChannelListen["Demos:Oneliner"]
Send a text to the channel and see it appended to the chat notebook.
Send a command.
Send a command by typing it in the input field at the bottom of the chat notebook and pressing the Return key.
You might also see messages from all other authenticated users who happen to send messages to the channel at this time, until you unsubscribe.