QR (“quick response”) Codes are bar codes that can be scanned by most newer mobile phones (with cameras) to quickly transfer information. It’s pretty simple; you turn on the QR reader (which will use your phone’s camera) and the phone will recognize and decode the information contained in the barcode. The new version(s) of Blackberry messenger incorporate QR codes to speed up the process of adding friends (it’s way better than trying to sync PINs). The example above is basically my email signature as a QR code.
You’re likely already starting to see them plastered everywhere (I’m going to make sure I have mine on my next run of personal business cards). If you want to generate your own QR code, (via Lifehacker) Kaywa.com has a free one you can use (you can then save the file as an image and use it however you see fit): http://qrcode.kaywa.com/