Chat
I have in no fashion attempted to create a full-featured chat client in the Terminal. There are already too many of those. Terminal has a built-in chat client accessible by the following commands; but as with the messaging commands, it is just for your amusement. I implemented it using Java's RMI interface, in order to learn the ins and outs (no pun intended) of that API.
That said, the chat client sports at least a couple of useful features. Like the great IRC protocol itself, you can create your own rooms and join in those of others, should you happen to know their names (see create chat room and enter chat room). But unlike IRC, every room is public and open to all known users (those who have logged in to the site). There are no security features, no channel ops, no banning--none of that. Think of these chat rooms as interactive radio stations. Or don't, because that's a lame analogy.
Anyway, take note of the talk command, because it will place the Terminal in a special mode in which almost anything you type will be sent directly to the chat room you are in, instead of to the Terminal's server. The way to return to the normal mode is to enter "untalk".
When you first enable the chat client, you will be in the default chat room for all users of VanCleve.com, called "Lobby". Therefore, if I actually had any users, this would probably be a busy room, and you'd want to join another. But I don't, and it's not, so there's no need. (Sigh!)
chat on
This turns on the built-in chat client. Thereafter, any chat messages sent to the server by any user in the same room as you will appear in the Terminal immediately, prefixed by the sender's username. Initially you will be in the default chat room, "Lobby". The chat on command is required in order to use the chat client at all. Whenever you enable (or disable) the client, it is remembered as a permanent user preference, so the next time you log on, if you have previously enabled chat, it will be reactivated for you automatically.
chat off
chat off disables the chat client, supressing any display of chat message and disallowing the use of chat commands, other than chat on, naturally.
say
The command say can be used to send a message to the current chat room, which is then displayed to all users in that room (including you). It should be succeeded by the message you wish to send.
talk
When you get tired of typing "say" before every chat message (or forgetting to do so and being ridiculed by the server), you can enter "talk". This will place the Terminal in a "talk mode", whereafter every line you enter is sent a chat message, more like a real chat client. If you need to enter a regular command, you must enter "untalk" to return to the normal mode.
create chat room
If you wish to create your own chat room, use this command. The room will be created if it hasn't already been, and you will automatically enter it. Remember there are no "private" rooms, so this is something like moving into a quite corner of a public building. If privacy is what you're about, choose a name that's hard to guess, as a password. That should do it, since there's no way to list all chat rooms. (Of course, in that case, the trick will be telling the room name to someone else without broadcasting it. If you know the person's username, you could use the message command for this.)
enter chat room
Use this command to switch from one chat room to another, provided the other exists. (If you're not sure about that, just use create chat room instead.) The room you last entered is not stored as a user preference, by the way, so when you log in and enable the chat client, you will be in "Lobby", regardless of where you were before. If you don't like that, then use a real chat client!