The early iteration of iTunes, with its now slightly confusing and broken up interface for browsing music, was hailed at the time for its otherwise simple layout of buttons and virtual knobs, and for its brushed aluminum aesthetic.
People snapped up songs. The iTunes Store passed the 500 million milestone in 2005, when Amy Greer of Lafayette, Ind., purchased Faith Hill's "Mississippi Girl" -- and won a golden ticket from Apple: 10 iPods, a gift card for 10,000 songs, and an all-paid trip for four to a concert by Coldplay. Customers of the iTunes Store have since downloaded more than 25 billion tracks.
One of the first big steps in making iPhones and iPods more independent from computers was adding a Wi-Fi iTunes Store right on the devices. Apple has since made the Store work on cellular networks too, letting people download music and apps on the go.
Over the years, Apple has tried all sorts of ways to further integrate the iTunes Store into its iTunes Software. One such effort was a sidebar that would check out what you already had in your iTunes library and offer suggestions for other music you might like (and might purchase by way of the Store).