iTunes increasing its dominance

The Apple unit already commands a 70 per cent share of the global market for digital downloads and is reportedly installed on 30 per cent of consumer computers.

It has sold four billion tracks since launching five years ago and as yet has no meaningful challenger in the digital music space thanks to the unprecedented popularity of its iPod and iPhone players - although Amazon and a host of handset vendors are attempting to force the issue.

Digital downloads accounted for 10 per cent of global music sales last year. That figure compares to six per cent a year earlier and is expected to top 40 per cent by 2012 based on In-Stat figures. 

But piracy is expected to have a massive impact on revenue. The $3 billion generated last year will only reach $4.2 billion when market share quadruples across the next four years. 

“Digital piracy continues to represent the primary challenge to online music service providers.