Apple's iTunes music store has sold its one billionth song. Alex Ostrovsky, from Michigan, purchased Coldplay's Speed of Sound and received a 20in iMac, 10 iPod players and a $10,000 iTunes gift certificate.

Apple's online music store opened in 2003 and came to the UK in 2004. The company claimed in January that it has over 80 per cent market share in the digital music download market and sells over three million songs a day.

At the current growth rate, the second billionth song could be sold later this year.

The iTunes store was one of the first places where consumers could legally purchase individual digital tracks.

Other services, including Napster and Rhapsody, beat Apple to the digital music market, but their subscription plans proved less popular because consumers lose access to their music when they cancel their subscriptions.

Prior to Apple's iTunes launch, record labels were reluctant to sell music as a download because of piracy concerns. Even today there are some holdouts, such as rock band Metallica which wants to sell its music as complete albums.

The success of iTunes is tied to that of the iPod. In terms of downloadable content, the device only plays music purchased on iTunes, locking out competitors such as MSN Music and Yahoo Music.