A QR (Quick Response) code is a block of black and white dots in a specific pattern - not dissimilar to a bar code - which can appear on a TV screen during a promo video, for instance, and be read by a camera phone.

This enables prospective fans who see it on their screen - and have downloaded a free QR code reader app - to access unique content such as exclusive tracks.

Invented in Japan in 1994, where ...