Fun trivia: in the early days of the ARPAnet, mail was delivered (at least on PDP-10's) by FTP-appending a message in to the receipients mailbox file. (Which wa

Fun trivia: in the early days of the ARPAnet, mail was delivered (at least on PDP-10's) by FTP-appending a message in to the receipients mailbox file. (Which was protected as append-only to world (owner, group, world).) Didn't last long, obviously, but that was back in the days when every site had a well-publicized guest login and you could telnet anywhere. (Well, OK, in 1972 there were only a few dozen nodes, but there were some really interesting ones to play with.) We used to play a game with telnet from HARV-10 where we'd telnet-chain around the world until someone dropped the connection or it got too slow.