Also known as Photocopylore, Xeroxlore is a modern medium of folklore. Xerox machines have been widely available in offices since the sixties, and certain nefarious people have been using them for their own purposes. Items are photocopied, and then circulated about the office. This often includes dirty jokes or cartoons, but also involves things more specific to the office environment, such as spoof memos.
As the copies fade with each copying, they are redrawn by others, creating slightly different versions of the same joke or drawing, much like a story changes after years of telling.
The humour is often bawdy, and also tends to involve sexual or racial stereotypes. Sometimes it will descend into mere obscenity. The privacy of the photocopying process allows perfectly for this type of humour to thrive.