Uwe Hermann | A slightly paranoid Debian developer

If you haven't yet read about it, some printer brands place tiny, almost invisible yellow dots on every page you print. These dots encode certain information (date, time, printer serial number, or similar things). I think you can easily imagine the security and privacy implications. The EFF has now cracked the DocuColor Tracking Dot code.

They have also written a program which decodes the dot patterns. The code is released under the terms of the GPL.

(via Boing Boing and CCC)