Next month’s Super Bowl will feature a sales promotion that is audacious even by that event’s over-inflated standards: Amazon.com, the largest online retailer, will offer as many as 1bn free downloads from its new digital music store in partnership with Pepsi and singer Justin Timberlake.

The promotion represents a coming-out party for the Amazon MP3 service, which launched in September. But it also poses a question: is a viable competitor to Apple’s iTunes digital music store finally on the horizon?