Hopefully somebody will link the thread of newsgroup posts from Berkeley way back in the day, where they discuss how people need to start marking jokes with some symbol because of an incident where a joke post was taken seriously to some detriment. It's a fun bit of history, I recommend it. The guy also says he invented the smilie face emoticon and includes posts from the very first people recorded to have started making all sorts of faces with characters. Unfortunately, I've lost it.