dr, does it look like this if so it is a QR code. There are phone apps out there for reading them.
I think you fire the app up on the phone and then run your lens over it.
You can really make them do anything. I've been thinking about getting the dog tags that have the codes on them.
If you dog runs away, and someone scans it, you get an e-mail notification with gps coordinates of the scan.
That's actually a good idea, and could be expanded to replace medical alert bracelets worn by many people. It could have medical history and contact #s.