The digital retailer last week launched Amazon Cloud Drive, offering customers in the US 5GB of storage for free for their music, video, photos and other documents.

Users can buy additional storage space, starting at 20GB for $20 (?12.50) a year, while Amazon MP3 customers who buy a new album will automatically get an upgrade to 20GB of free storage.

Uploaded tracks can then be streamed through the browser's Cloud Player or a dedicated Android app.

One label executive complained ...