Well these things are not alien messages or terrorist code, they are a simple advertising tool. This is how it works.
Although initially used for tracking parts in vehicle manufacturing, QR Codes are now used in a much broader context, including both commercial tracking applications and convenience-oriented applications aimed at mobile phone users (known as mobile tagging).
QR Codes storing addresses and URLs may appear in magazines, on signs, buses, business cards, or on just about any object that users might need information about. Users with a camera phone equipped with the correct reader application can scan the image of the QR Code to display text, contact information, connect to a wireless network, or open a web page in the phone’s browser. This act of linking from physical world objects is known as a hardlink or physical world hyperlinks. Google’s mobile Android operating system supports the use of QR codes by natively including the barcode scanner (ZXing) on some models and the browser supports URI redirection, which allows QR Codes to send metadata to existing applications on the device.
So having said all that would you like to create your own message or link to a website?
Go toqrcode.kaywa.com enter the test you want and click generate this will give you a meta string and also a simple picture you can just save and put on your website.