writes "The America Online protocol(Connecting, Logging In, Joining Chats, etc..) has remained a mystery for most of its life. The only way one could log into their AOL account was via the AOL software. A few months ago, some people set out to break down the AOL protocol and open the door for alternative America Online software. This document is the result: The AOL Protocol.
A sign on example for Visual Basic programmers has been written and is available here."
I suspect a fair number of people never try Linux or one of the BSDs because they're moderately happy with AOL as an ISP, and switching OSes would mean switching ISPs at the same time. A shame that AOL doesn't make this kind of information more easily available.