A technology for using the Internet to send real-time, text-based messages. Internet Relay Chat (IRC) is defined in Request for Comments (RFC) 1459.
IRC is a client/server technology in which users employ IRC client software to connect to an IRC server or hub. Clients can then connect to an existing chat group (also called chat room or channel) and type messages to other users currently in that group. Chat groups are identified using a pound sign (#) prefix. Messages are transmitted in real time and can appear character by character on the recipients’ client software if the person sending the message types slowly enough.
Depending on how the chat server is configured, users might be able to create their own chat rooms and hold private discussions. Some chat servers require that you register once to obtain a unique nickname, while others allow you to select a nickname for the current session only. Some Web sites also offer Web-based interfaces to their chat servers.
Microsoft Exchange Server version 5.5 includes an IRC-based chat server that you can use to set up public or private IRC sites.