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This means sales of snippets of the song to be used as a ringback have exceeded 500,000 copies or the same number required to achieve Gold status in the album, single and ringtone charts.

 
Ringtones and ringbacks fall are known as mastertones, which combine sales of both types of downloads.  Ms. Keys "No One" has reached Double Platinum in the mastertone category by surpassing 2 million in sales.

In a report last month by IDC, it was predicted ringback sales would overtake ringtones by 2010 to become the largest source of mobile entertainment revenue.

IDC says wireless service revenues will hit $US800 billion by 2011. $US40 billion, or some 5 per cent of that total, will involve mobile entertainment.