These are the special chat commands that you can use while in Battle.Net.  Note that you can press F1 to view some of the basic chat commands, or other Battle.Net help features. Also note that these are "Diablo" chat commands, and I have not included commands that may otherwise work for another Battle.net game, like StarCraft.

GENERAL CHAT COMMANDS:

• /whois <player>: Searches for another player in public chat rooms and games. Also /whereis <player>

• /who <channel>: Gives you a list of the people in that channel. If it is a private channel, you will see the OP of that channel distinguished with the [   ] symbols.

• /whisper <player> <message>: Sends a private message to the player specified. This also works if the player you want to whisper is in a game or is in a different channel. (Short form: /w, /m or /msg)

• /squelch <player>: Ignore messages from this player. The said player will be marked with a red X in place of his or her character icon. Also /ignore <player>

• /unsquelch <player>: Turns off squelch for this player.

• /join <channel>:  Lets you join the chosen channel. Also /channel <name>

• /users:  Lets you know how many users/players are online, how many games are in progress, and how many channels exist on Battle.net at that specific time.

• /rejoin:  Lets you rejoin the current channel, used mostly if you want to be at the end of the list or you want someone else to be on top of the list. Also /resign

• ALT-V:  Toggles player joining/leaving notifications.

• ALT-N:   Hitting this while highlighting a name at the right of the chat screen (the frame that lists the users in the channel) will automatically paste the name you highlighted on your message bar. This replaced the "double-clicking" a name so you can say a user's name without typing it out. Double clicking on a name at right of the chat screen will now show you the user's profile.

• /time: tells you both the Battle.net time and your local time

• /away <reason>: This is a new command in Battle.net. This command can be used when you're gonna go AFK or OTD. The reason you give will show (in parentheses) when any person tries to do a /whois command on you. For example, ~Lag_Monster~ is logged on at #1010101, and is currently at Open Tech Support channel. User is away (talking on the phone). To disengage from "away" mode, you simply type in /away again to toggle it.

• /whoami: Uhm, tells you who you are, where you are, and your account number (doh!).

• /dnd <reason>: This new command (introduced in the 1.05 patch) lets you refuse whispers from everyone. They will see the "reason" you typed when they try to whisper you. Good command if someone is whisper-spamming you.

• /me <message>: Otherwise called as the "emote" command, this command is more a novelty than a necessity. It emulates "thinking out loud" and is shown in yellow to separate it from normal chat.

To quickly enter a player's name, highlight the player's name from the list at the right and hit ALT-N. Double-clicking on his or her name will reveal that player's profile.

SPECIAL CHANNEL OP COMMANDS
(for private and guild/clan channels)

* Channel OP:  He or she is the one who is in charge of a private channel.  The OP is the one who assumes responsibility for the etiquette and language within the private channel. A brown gavel or hammer, instead of the character icon, marks the channel OP (aside from the fact that he or she is always on top).

• /kick <player>:  The ability of the channel OP to "remove" a player from the channel.  This is often used as a tool of discipline or just for fun in most guild channels. Players who get "kicked" are automatically transported to a channel called "THE VOID."

• /ban <player>:  This is the most powerful command that a channel OP can use.  It will literally "ban" a player from the present channel, and he won't be able to re-enter it, unless he or she is unbanned by the OP or if a new OP takes over.  This is often abused by many channel OPs, but it is undeniably the best channel quality control tool in Battle.Net. A banned player also cannot view who are in the channel when he uses the /who <channel> command. People who are banned from a channel are also automatically transported to "THE VOID" channel.

• /unban <player>:  This command negates the /ban command the OP has given a particular player, allowing that player to successfully re-enter the channel.

• /designate <player>:  This allows the OP to choose his or her successor.  The player who is designated will become the channel OP if ever the current OP decides to leave or step down.

• /resign or /rejoin:  This command simply allows the OP to step down as a regular channel chatter.  If the OP did not designate a player to a successor before he or she executed the command, the second player in the list (below the OP) will become that channel's next OP.