From what I see I discovered that many people on this forum need to know basic/useful commands for the alterIWnet. One of them is chatmodeirc.
Type in game console: bind <key> chatmodeirc
Then press your bound key and type: /server <server> , f.e. /server irc.rizon.net
Then you are connected to server.
Now type: /join <channel> , f.e. /channel #Rizon
That's all. You will have your in-game nickname while on chat. You can also change your nickname by typing /nick <nickname>
Hope that helps. Good for matches when we want to talk only with people from your clan, other people like spec won't see what you type. It's much faster than opening steam/xfire overlay.