If you leak to the press, you may not want to get caught. If you plan to print documents, or if you are just interested, read up on your yellow tracking dots here:
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. When one person asked his printer manufacturer about turning off the tracking dots, Secret Service agents showed up at his door several days later.
Is your printer spying on you? Full list of manufacturers who use secret ‘tracking dots’ revealed
Wikipedia explains Machine Identification Code