Imagine that every time you print a document, it automatically includes a secret code that could be used to identify the printer -- and, potentially, the person who used it. Sounds like something from a spy movie, right?

Unfortunately, the scenario isn't fictional. Most color laser printers and color copiers are designed to print invisible tracking codes across every single printed page of their output. These codes reveal which machine produced a document and, in some cases, when the document was printed or copied.

For a tutorial on viewing your printer's secret dots, visit http://www.instructables.com/id/Yellow_Dots_of_Mystery_Is...

We are grateful for the support of the California Consumer Protection Foundation.

Special thanks to Dan Oberbauer for sound effects. (less info)