QR codes provide a way to link physical objects and locations to online content and resources using mobile devices. The document discusses how QR codes work and their history. It also provides examples of how QR codes can be used on a college campus to direct students to course materials, disseminate contact information, and link people to further information. Some challenges with QR codes are that users need a mobile device and QR code reader, and standards for readers are still being developed. However, QR codes allow for experiential learning by bringing online resources into physical experiences.