You know, just about every music store out there uses its own proprietary form of DRM, whether it be Napster, Rhapsody, iTunes, or Wal-Mart. DRM limits your usage of the song, as in how many times you can burn it to CD, how many computers it can be one, etc. However a new generation of music stores, like the Amazon music store and the Zune Marketplace, are popping up with DRM-free tracks. You can put these songs on as many devices as you want, burn it as much as you want. And oh yeah, iTunes plus is iTunes' DRM-free store. Because MP3 does not support DRM, iTunes and iPods use AAC and other music stores and players use WMA. These days AAC and WMA have outperformed the revolutionary MP3, so a WMA would sound better than a MP3 using the same amount of space.
My second point is that there is basically
two types of audio three I make that types of audio, uncompressed, lossless compression, and lossy compresssion. Uncompressed is what comes on CDs and what recording studios use. They take an incredible amount of space and normal consumers tend to ignore them. Then there's lossless compression, which has the almost the same quality as uncompressed but uses much less space. Again iTunes uses a different format than all the rest Windows based stores. Finally there's lossy compression, which is usually what you download. AAC, WMA, and MP3 are all lossy. They are the most commonly used because they sound okay to most ears and save space. These different lossy codecs all use their own unique ways to compress, dropping some extra highs, combining similar mids, etc. Although there are WMA-MP3 converters etc, it is not recommended to use them unless absolutely necessary because they further compress an already compressed WMA with MP3 compression techniques, giving you the worst of both worlds. Same thing applies to when you burn a WMA to CD and rip it back in MP3. Oh man, there's so much more in the world of DRM and audio compression, but that's the basics.