derf /derf/ v.,n.
[PLATO] The act of exploiting a terminal which someone else
has absentmindedly left logged on, to use that person's account,
especially to post articles intended to make an ass of the victim
you're impersonating. It has been alleged that the term
originated as a reversal of the name of the gentleman who most
usually left himself vulnerable to it, who also happened to be
the head of the department that handled PLATO at the University
of Delaware.