There have been a lot of advances in this recently - I'll have to go and find some of the submissions here on HN that suggest that it's not as far fetched as pe

There have been a lot of advances in this recently - I'll have to go and find some of the submissions here on HN that suggest that it's not as far fetched as people often assume. You'd expect it to be science fiction to read sound off vibration of leaves in a room, but that's been done. You'd expect it to be science fiction to eavesdrop using a cell phone's accelerometer, but that's been done. Correlate several frames together, increase the contrast, who knows what might be possible. Or, you know, build the next "To Do" list manager or Candy Crush replacement.