In the older days you cold read the ground wire of a house and figure out what a keyboard attached to a computer was typing.
No. I am not kidding. (https://www.usenix.org/legacy/event/sec09/tech/full_papers/vuagnoux.pdf) This was specific to PS/2 keyboards (pre USB) at the time. Though, I imagine if you had a HAM system connected to the same power/ground source as your PC/keyboard you maybe could have pulled it right out of the air.
Maybe it's time for me to make a new sub "Are you paranoid yet"? or something like that....
Oh, the screen reading thing happened too. It was called Project Tempest and could re-create what was on a CRT (computer or TV) from a distance by picking up the emissions. (This was done in 1985, for ref).
The longer you talk with me, the more freaked out you are going to get. It's kind of a thing o.0