I know I’ve read about this in the past, and yet I always forget: the EFF reports on color laser printers putting tracking info in your printouts. So, yes, if you print something on a color laser printer, it is possible there is an embedded code which would allow the printout to be tracked back to the printer that produced it. The EFF page has some nice information about finding and decodinig the yellow dots used for these markings, as well as a list of printers that do and do not print these tracking dots. They are continuing to update their list, so if a printer you use isn’t listed, don’t forget to check back later. I’ll be checking whether the one at my office is on the list on Monday.