Strange but True: Leaving Trails Behind

It is one thing to track down sent information through the Internet Protocol(IP) address where you last logged in, but tracking through printers used is something that looks like next to impossible.But tracking through printers can be done. the Electronic Frontier Foundation (EFF), a consumer privacy group based in San Francisco in the United States, was able to crack the code behind tiny tracking dots that common laser printers hide in every document.The tracking dots-which are yellow-are invisible to the naked eye, according to Seth Schoen, an EFF researcher. but when viewed under blue light and through a magnifying glass, the dots can be used to identify the date and time a document was printed and the serial number of the printer, said Schoen.
Secret service officials in the US revealed that more than 50% of fake money comes from color laser printers. so, they are using only the code to track down counterfeiters and not to pry on people's computer activity.
Privacy advocates, however, expressed that law enforcement agencies even common citizens may abuse the technology and that there's no law to stop them. EFF lawyer Lee Tien said that the "problem is that tracking counterfeiters also means putting in technology that allows you to track every document."
EFF is publishing light printers that produce codes, including at least 80% of models on the market. "we think people ought to know what their printers are saying about them," said Schoen.
(Feds Can Connect Dots to Your Computer Printer )