From Apple.com: iTunes Now Number Two Music Retailer in the US
iTunes Customers Top 50 Million
CUPERTINO, California–February 26, 2008–AppleÂ® today announced that iTunesÂ® (www.itunes.com) is now the number two music retailer in the US, behind only Wal-Mart, based on the latest data from the NPD Group*. Apple also announced that there are now over 50 million iTunes Store customers. iTunes has sold over four billion songs, with an incredible 20 million songs sold on Christmas Day 2007 alone, and offers the world’s largest music catalog of over six million songs from all of the major and thousands of independent labels.
iTunes is successful because it’s convenient, cheap, and easy to use. It’s instant gratification at its finest.