http://www.ghacks.net/2015/01/31/kaspersky-qr-scanner-make-sure-qr-codes-are-not-malicious/So-called QR Codes are very similar to shortened urls. The core similarity is that you don’t see where the link takes you when you activate it.
QR Codes are used in many different locations and situations. On advertisement so that you can look up additional information about an offer, in shops, public transport, magazines and on websites.
The recently released WhatsApp Web uses a QR Code for instance to link the account on your phone and the web interface.
Since it is easy to create them, they can be misused easily as well. It takes no effort to display codes on websites and minimal effort to create stickers of codes.