Yes, that's billion -- with a 'b'.
A teenager in the US recently purchased the one billionth song from Apple's digital music service iTunes.
Apples's Chief Executive said the milestone represented "a major force against music piracy and the future of music distribution as we move from CDs to the internet".
According to Nielsen Soundscan, traffic to the iTunes website grew by 241% in 2005. The number of users rose from 6.1 million to 20.7 million.
Approximately 14% of active Internet users accessed the service regularly. Teenagers were the largest group of visitors and were twice as likely to use it than any other group.
It's not good news for everyone, though. Internet-based music purchases came at the expense of CD sales. Nielsen found that CD purchases in the US declined from 763 million in 2001 to 619 million in 2005.