The launch of music tracks free of digital locks on iTunes has been overshadowed by the discovery that they contain data about who bought them. Some fear this data could be used to identify the owner of the tracks if they turn up on file-sharing sites.
The tracks from record company EMI cost more and are of a better quality than standard iTunes songs.
Apple has yet to comment on what it plans to do with the information embedded in the music files.
The tracks without the digital locks, known as Digital Rights Management (DRM) technology, officially went on sale on 30 May under the iTunes Plus banner. The downloads cost 1.69 in Australia.
Apple uses a technology known as Fairplay to limit what people can do with downloads. Fairplay can be circumvented by burning tracks to a CD and then converting them to another format.
