University of California - Berkley's library web catalog, also known as Oskicat, has recently started to use QR codes to help students and researchers locate books and other documents online.
In the lower right hand section of a catalog page you will see a QR code. When scanned, the code will give you a general listing of where else the book or document can be found online. While this application is not as interactive as it could be, it does illustrate how yet one more industry is making use of 2D barcode technology.
To maximize the usefulness of 2D barcodes, the university might consider developing a mobile page for each book or document in the catalog, which not only provides general catalog information, as it does now, but to add descriptive text about the book or document. Additionally, the library should add some instructional or explanatory copy next to the QR code to inform students and researchers what the code is, how it can be scanned and what it links to.