Printer Micro Dots Allow Your Documents to Be Tracked

Imagine that every time you printed a document, it automatically included a secret code that could be used to identify the printer… In an effort to identify counterfeiters, the US government has succeeded in persuading some color laser printer manufacturers to encode each page with identifying information. That means that without your knowledge or consent, an act you assume is private could become public.

Another reason to send the Electronic Frontier Foundation a few dollars.  And then print out their test sheets and send them in so they can try and figure out which printers are configured to do this stuff.