The Fidonet is an amateur network of Bulletin Boards and messaging systems which started in 1984. Its heyday was in the late 1980s and early 1990s before the Internet became cheap enough for everyone. It was the first time that many people had been able to communicate via their computers with other computer users and from its beginnings it grew within ten years into a worldwide network of over 30,000 systems. But when Internet Service Providers began offering cheap subscriptions the Fidonet gradually saw a falling away. From its peak in the mid-1990s there has been a slow but steady decline in membership although there are still, at the time of writing (2005), around 8,000 systems. Originally Fidonet made use of dial-up connections for transporting messages and files but this did make propagation slow and expensive. With the advent of "always-on" broadband connections, the Fidonet protocols are now largely used over the Internet for fast, cheap delivery of mail.

When the Fidonet started the only modems available ran at 300 bps - inconceivably slow by today's standards! By 1989 9,600 bps modems were available but they were expensive (1,000 pounds in the UK). Speeds gradually increased and by the late 1990s modems had reached their present speed of 56,000 bps and the price reduced to a fraction of what earlier modems had cost. Development of the telephone-line modem has not progressed for the last few years, presumably because of the availability of DSL connections which run at speeds starting at ten times the speed of the fastest dial-up modem. Many nodes can still still be dialled via POTS (Plain Old Telephone System!) but an increasing number are contactable over the Internet.

A Fidonet "node" can be a Bulletin Board System (BBS) or it can be a single user. Although most nodes now have access to the Internet the operators of these nodes still prefer to exchange mail via Fido Network Technology (FTN) as it seems to be more personal. For instance, the equivalent of Internet newsgroups or mailing lists are called echomail conferences in the Fidonet. Although anyone can read messages in these echoes, each message is usually addressed to a particular person, especially if it is a reply to a previous message. It is then obvious whose comment is being answered which makes much more sense of reply chains.

The Fidonet is run entirely by its members. This is a great strength but it is also its greatest weakness. The strength is that members can organise things as they wish as long as they adhere to a fairly basic policy. The weakness is that if a member chooses to ignore the basic rules or simply does not give his system the attention it needs for smooth running it can affect adversely the running of a great many other systems.