FidoNet: n.

A worldwide hobbyist network of personal computers which exchanges mail, discussion groups, and files. Founded in 1984 and originally consisting only of IBM PCs and compatibles, FidoNet now includes such diverse machines as Apple ][s, Ataris, Amigas, and Unix systems. For years FidoNet actually grew faster than Usenet, but the advent of cheap Internet access probably means its days are numbered. In mid-2001 Fidonet has approximately 15K nodes, down from 38K in 1996 — and most of those are probably single-user machines rather than the thriving BBSes of yore.