Initially, most IRC servers formed a single network, to which new servers could join without restriction, but this was soon abused by people who set up servers to sabotage other users, channels or servers. When, in August 1990, server eris.berkeley.edu remained the only one to allow anyone to connect servers, IRC server operator Greg Lindahl broke away and started EFnet, the Eris Free Network. The resulting argument split the IRC community of admins, but almost all admins (and users) ended up joining EFNet.
Continuing problems with performance and abuse eventually led to the rise of another major IRC network: Undernet, which split off in October 1992.
In July 1996, disagreement on policy caused EFnet to break in two: the slightly larger European half formed IRCnet, while the American servers continued as EFnet.
Although there is no official website, more information about EFNET can be found on http://www.efnet.info