QR codes, what for?
QR codes (for «Quick Response») are images encoded like bar codes that can contain all kinds of information, such as a sentence. The image opposite is a QR code containing the text: « Bonjour! Je suis un code QR. »
Ultimately, you have to download an application on your mobile to be able to read them. Most cell phones with a camera can read QR codes. The code in question may contain useful information such as the address of a website, but also be used to trigger an action such as sending an email or connecting to a Wi-Fi network.