What is the "finger" protocol and how can I use it?

The finger protocol, defined in RFC 1288, is a way to obtain information about users on a remote machine. A user running a finger client can query a server for a list of users or to obtain information about a given user. This requires a finger server to be running on the target machine.

RFC 1288 contains the complete protocol specification. It can be found at http://www.faqs.org/rfcs/rfc1288.html.