It’s completely unrelated to dot-matrix printing.. or is it? When I visited the EFF a few weeks ago, they blew our minds by showing us a pattern of coded dots which identify the printer make, model, date and a number of other things. The dots are printed out by most colour printers and are visible only under blue light.
Approximately 10 years ago, the US Secret Service asked a number of printer manufacturers to include this undocumented “feature” in their products – which they eagerly complied with. This isn’t restricted to the US, and is actually not so new PC World had an article about this a year ago.
It does make you wonder how many other hidden features exist inside our technologies and whether they will ever be revealed. I have faith that the growing DIY hardware hacker culture, as seen in Make magazine, SquidLabs Instructables and other places, will aid in revealing more of these insidious Easter eggs over the next few years.