Meet the QR code!

QR code. Quick Response.
The next stage in the development of well-known barcodes. Any information is encrypted in the code - text, url, SMS template ... in Japan, it is already going to encrypt the voice in the code.

What is the trick?
You have a code reader and a camera on your phone.
You point the camera at the code and - voila! - instead of black and white dots, you receive information encrypted in it on the phone screen. There are no buttons except “to turn on the program”.
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More details can be read on the links:

What are QR codes?
The use of QR codes in marketing. Japanese experience
QR codes: discussion on Habré