A QR code is like a bar code. It can be read by a mobile phone with a camera. The mobile device must have a QR reader installed on it.

The QR code usually contains  a web site address and will automatically connect the mobile phone user to the address of the web site contained in the code. However up to 3 kilobytes of information can be stored in a QR code which is about 3000 text characters.

This picture shows the QR code for the address of this web site.

QR codes are used on advertising and on product packaging so that people can quickly get more product information via their mobile phone.

QR stands for Quick Response and is a type of bar code that was invented in Japan where they are very common. They are becoming more common in Europe as well due to the growing use of mobile devices to access information on the web.

They can help to transcend language barriers, as web site addresses are all written in latin script. However,  the majority of world's population do not use a latin script in their native language. QR Codes help in this respect as no keyboard input is required and they are placed in context, on the product or near a service.