In 2001, Apple launched the MP3 player that changed the landscape of today's mobile market. The iPod was the renewed motivation behind many of Apple's ambitious and revolutionary projects.
Apple's iTunes Store monetized digital music sales, while virtually shuttering every brick and mortar music retailer except Walmart and Target. Apple is now the world's largest music retailer.
For the record, Apple announced the iPod on October 23, 2001, with the first retail sales taking place on November 1, 2001.