(channel) is any name of a channel. (name) is a users nickname or account number
/whois (name) or /whereis (name) - Tells you where somebody is and their account number
/squelch (name) or /ignore (name) - Ignores somebody. You won't see any messages they type. Ignored people have a red X on their picture.
/unsquelch (name) or /unignore (name) - Lets you see messages from people you have ignored. The red X dissapears from their name.
/users - Tells you how many users are on battle.net, how many channels they are in, and how many games they are in.
/w (name) or /whisper (name) or /msg (name) - Sends a message that only they can see. Whispered text is grey.
/join (channel) - Makes you go to the a channel.
/rejoin or /resign - Puts you at the bottom of the names list.
/time - Displays Bnet's time
/away - With a message, puts you in away mode. Without a message, takes off away mode. People who do a /whois or whisper you see your away message.
/unban (name) - Lets a banned person back into the channel.
/kick (name) - Kicks a person out of the channel. They can then go back into the channel.
Alt W - Whispers
Alt V - Turns the Enter/Leave notifications on and off.
Alt J - Join a game
Alt C - Create a game
Alt H - Join a channel
/who (channel) - Lists all the users in a channel
Channel operator commands
/ban (name) - Kicks a person out of the channel and pervents them from coming back in untill unbanned or there is a new operator.
Keyboard shortcuts
Alt Q - Quits Diablo