You are being tracked and tracked and tracked. Your Google searches, your phone gps, and much, much more help those tracker types to know you better than you know yourself. It's not just for ads. It's really beyond belief how crazy this has gotten. Cameras on laptops and devices like Kinect can easily be turned on remotely without you knowing it. It's all about how interested they are in you. David Petraeus actually said that your dishwasher will be watching (not washing) you soon.
http://www.wired.com/dangerroom/2012...eus-tv-remote/ . The world we grew up in is long gone. Heck, they were matchng ads to email content back in 1648.