A two-dimensional barcode format that efficiently stores alphanumeric characters; often a URL. QR codes are often used for consumer applications as they are more recognizable as being a consumer barcode than other formats.
Data Matrix has started to replace QR Codes in several major deployments as Data Matrix is not encumbered by patent issues.
Quiet Space
A QR code must have an area of white quiet space around it such that it can be properly identified by a reading device.
Example
This is a QR Code for http://gototags.com
