A 'trick' used by the file-sharing community in order to hide their files on these anonymous FTP servers was to create some nested directories with these kind of keywords. The FTP server allowed you to create the directories as well as access them (if you knew the full path) but on Windows they would just cause errors or crashes if someone tried to access them. Combine that with the ability of creating directories with just spaces as names and you could hide quite a bit of stuff from the unsuspecting FTP server administrator.