QR codes are two-dimensional barcodes that can be read by smartphone cameras and contain information to direct the user to a website or other online content. The document discusses how QR codes are being used in various industries like retail, publishing, and education. Some benefits of QR codes are that they are low cost, easy to use, mobile, and provide instant access to online information. Potential issues include slow mobile internet speeds, data costs, and lighting or software problems reading the codes. The document also provides an example of how the Sydney Design 08 Festival used a QR code in their program to provide special offers to users who scanned the code with a mobile application.