Agent Elise says, "Welcome to Dark Queen MUSH. I am agent Elise, this is agent Green, we are here to help you adjust to your first moments here in Dark Queen. As you play the game, you will spend most of your time talking to fellow users, so the first thing you'll need to learn is how to speak. You can speak using the 'say' command, simply type in say then the message you want to speak, e.g. 'say hello'. In order to continue beyond this tutorial, you will need to say 'begin intro' now.
It's not exact, but that is the basic gist of the first part of a tutorial I wrote for a mush I was working on before it got completely wiped out. Without context it may not be so easy to see, but you may have noticed that the move commands are not explained at all. Before I would teach a new player how to move, I would require them to know how to speak. As I remember, the intro began with some quick notes on how to contact me for help as well.
Chatting is a fundamental system to all MMOs. In fact, even for solo players I would posit that you cannot play an MMO for any significant length of time without chatting. This should also be important to producers, since the amount of chatting a player does in their first few hours can be an overriding element in new player stickiness. Of course most players work these things out in-spite of the developers miserly hoarding of the information, but you never want to put yourself in a situation where a player is joining the game in-spite of your best efforts not because of them.
Also this wouldn't be such an issue if the chat interfaces were simple, but in MMOs they tend to be rather complicated. Even more so, unlike MSN or Skype where the added complexity is added in a manner that partitions it away from the act of chatting itself, in an MMO all of the complexity is based around the basic chat line. You'll need to manage tabs in order to view different channels you may be chatting on, which may or may not effect which channel the next message you type will go to. Talking across multiple channels may be a matter of mouse clicking to a different channel, a different tab, or the use of a / command which in turn may be '/[channel]' or '/[channel],' and may or may not be capitalization agnostic. And all of this is required just to learn how to say something to the person you actually meant to say something too rather than the entire zone or even the entire world.