is a term in the computer security world for being able to read the contents of (amongst other things) computer screens remotely by looking at the electromagnetic emanations leaking from the monitor. You can essentially build a modified analogue TV which can tune into a computer's monitor and see what the remote user sees. This obviously caused quite a freak-out in security circles when it was discovered.
The usual way to deal with it is increased mechanical shielding around monitors to reduce the signal emission, but last night I read about a project
(PDF) to defend against electromagnetic snooping by modifying the font rendering
(I have no larger point here, I just found it fascinating.)