Amazon may not be the sales behemoth in music that it is in books, but it's still got a sizable, solid business, both in CDs and digital, downloadable music. The CD business is about as straightforward as you can get -- buy CDs on Amazon and have them shipped to you. For buying digital music, Amazon takes an approach that almost seems quaintly old-fashioned in the fast-moving digital music marketplace: Buy individual MP3s from Amazon and play them on a device. The selection is sizable (currently more than 22 million songs), and Amazon has a Web-based MP3 store as well as an Android store.
As for iOS devices, there's no iOS Amazon MP3 app. You have to buy digital music on an iOS-optimized version of the Amazon website. And when you buy the music, it won't show up in iTunes.
Amazon's digital music sales have been gaining serious market share, likely driven by music sales on its Kindle Fire tablet, says the NPD Group. It reports that in the fourth quarter of 2012, Amazon had 22 percent of the market for music downloads, compared to 15 percent in 2011, 13 percent in 2010, 10 percent in 2009 and 7 percent in 2008.
iTunes, though, was still dominant in the fourth quarter of 2012, NPD reports, with 63 percent market share, although declining slightly from previous years, with 68 percent market share in 2011 and 69 percent in 2009.
The most innovative part of Amazon's music ecosystem is the Amazon Cloud Player, which lets you stream your music from the cloud to any computer or Android or iOS device. Any MP3 you buy from Amazon gets put into the cloud. And you can add digital music to it that you didn't buy from Amazon, such as music that you've ripped to a digital format yourself. It's not a subscription service like Spotify that streams music that you haven't bought, so you only get access to what you've purchased or to what you've copied.
That's it for now. Amazon appears to have its sights on launching a Spotify-like subscription music service. Reports say that it is in talks with music companies to start one. If that ever happens, Amazon's music ecosystem could become a juggernaut.
The big question for Apple these days when it comes to music is whether it can replicate the success of its digital music behemoth iTunes with its just-announced streaming Internet radio service, iTunes Radio.
There's no doubt that iTunes has been a raging success: As of April 28, 2013 -- at the tenth anniversary mark -- the iTunes Store has sold over 25 billion music tracks and is available in 119 countries, each with a selection of at least 20 million songs (the U.S. iTunes store alone carries over 35 million). According to NPD, the iTunes store accounts for about 30 percent of all music sold worldwide and 63 percent of all digital music sales.
There have been some tweaks since iTunes first started selling music. iTunes Plus music files are now free of DRM restrictions and are encoded as 256Kbps AAC files. (Note: They still contain purchaser information.)
Music lovers with iOS devices are not limited to the iTunes Store; Apple's App Store includes the streaming services Spotify and Pandora, and the music-matching services Shazam and SoundHound. There's even a karaoke game for Glee fans, called, appropriately enough, Glee Karaoke.