Tracking what you print
A little-noticed system that allows printed documents to be tracked by government agents...is baked in to many popular color laser printers and photocopiers, including those made by Brother, Cannon, Xerox and HP, according to this list compiled by the Electronic Frontier Foundation. It embeds almost invisible tracking dots onto documents that uniquely identify the machine that printed them.
The enables the tracking of currency counterfeiters, but the EFF has been warning for years there's nothing that prevents government spooks from using them for broader types of surveillance....According to the EFF, printer manufacturers added the technology at the direction of the US government, most likely the Secret Service.
And to think we used to point at the USSR's compulsory registration of typewriters as an indication of how unfree and bad it was.