FTP stands for File Transfer Protocol, and is a set of ground rules (a ╥protocol╙) that allows two computers to exchange files over a network. FTP was developed in the 1970s by users of the Advanced Research Projects Agency network, or Arpanet. FTP is the official file transfer mechanism of the Internet (Arpanet's larger successor) and therefore is supported by hundreds of thousands of machines.
Fetch implements one part of FTP, the ╥client╙ side. Therefore it can communicate with any connected machine that has a ╥server╙ program. Some of Fetch's features will not be available on certain servers -- this is because the other machine does not support the feature (e.g. not all machines have sub-directories) or because the server program does not implement the complete FTP specification.
