Even your printer is spying on you! Hard to believe.
Intrigued by the new project of the Computing Culture's research group directed by Chris Csikszentmihalyi, I discoverd Seeing Yellow. So if you think that you need to hide your IP address and remove spywares, well maybe spies are around you in your tangible environment for a while now!
When you print on a color laser printer, it's likely that you are also printing a pattern of invisible yellow dots. These marks exist to allow the printer companies and governments to track and identify you -- presumably as a way to combat money counterfeiting.
Now Seeing Yellow has a tangible-antispyware available for you and this by calling your printer maker (and more)
Glass invaders designed by Sebastien Messerschmidt