By accident I found this (see my earlier post about QR Codes at MIDEM):

Japanese Promote Music With QR Codes

The J@pan Inc Music Media Watch Newsletter has an interesting feature about the increasing use of QR codes to promote music in Japan (QR Codes being a two-dimensional barcode). “Many mastertone and full-song mobile download sites have magazine tie-ups in which a QR code is included in an article or advertisement to provide a free song or listening sample. Local indie bands include a code on their flyers linking to their mobile sites. Several CDs here include codes that link to ‘extras’ such as mastertones, videotones and artist wallpaper.” It seems to be a good way for indie artists to offer samples of their music.

See also: Yesterday MIT Advertising Lab also wrote an article about QR Codes used in Japan.