Your laser printer will give you away
It was big news last month when a couple of researchers at Purdue announced a way to trace documents back to their original printer or photocopier, but it turns out that Xerox and most other laser printer and copier makers have been selling devices that encode serial numbers and manufacturing codes on everything they print out for years. They've been doing it at the behest of the US government, which uses it as a tool to fight counterfeiting, and there's no way to disable or get around it. But if you do want to know whether or not that manifesto or threatening letter you just printed out can be traced back to you, PC World recommends shining a blue LED on the printout and grabbing a magnifying glass.
