Eva Galperin writes:
Your digital camera may embed metadata into photographs with the camera’s serial number oryour location. Your printer may be incorporating a secret code on every page it prints which could be used to identify the printer and potentially the person who used it. If Apple puts a particularly creepy patent it has recently applied for into use, you can look forward to a day when your iPhone may record your voice, take a picture of your location, record your heartbeat, and send that information back to the mothership.
This is traitorware: devices that act behind your back to betray your privacy.
Read more on EFF.