Internet Relay Chat is text-based Internet-wide multi-user communication system, where discussions are organized into channels. The popularity of IRC is based on the fact that the IRC networks consist of servers linked to each other. The users then may connect to any server and join world-wide discussion channels send messages to users on any other server. For further, possibly more up-to-date, technical information, type IRC to your favourite web search engine.
Jarkko Oikarinen started Internet Relay Chat, IRC, in 1988. With the help of at least hundreds of volunteers during the last ten years IRC has become as one of most widely used services in Internet.
The Dvorak Award was granted to Jarkko Oikarinen in 1997 for developing IRC.
A Special Recognition Award (so-called mini-millennium) was granted to Jarkko Oikarinen by The Millennium Technology Prize Foundation in 2005 for developing IRC.
IRC Homepage at FUNET contains more information about IRC.