[ddt_Osprey]

Jesus, I wasn't even going to read this article, but holy shit, am I glad I did.

  Using more precise sensors, the same MIT 
  researchers went on to develop systems that 
  can distinguish between different people 
  standing behind walls, and remotely
  monitor breathing and heart rates with 99 
  percent accuracy.

  A system called “WiKey” presented at a 
  conference last year could tell what keys 
  a user was pressing on a keyboard by 
  monitoring minute finger movements. 

  And a group of researchers led by a Berkeley 
  Ph.D. student presented technology at a 2014 
  conference that could “hear” what people were 
  saying by analyzing the distortions and 
  reflections in wi-fi signals created by their 
  moving mouths. 

Man, I was about to blow this off as yet another MAC address sob story. I totally was not anticipating doppler effects and radar-style reflection/signal strength analysis.