Apple finally launched their iTunes Match service this week. If you don't know what that is, I'll explain briefly. In the eight years since Apple opened their iTunes Music Store, they have been amassing an enormous collection of digitized music that they have the legal right to sell. If you buy a song from them, and your computer crashes, you can redownload that song again whenever you like, since, rather than a physical medium like a CD, what you've bought is the right to have that digital file. What Apple has done with iTunes Match is allow you (for $24.95/year) to redownload any song you have in your iTunes library, whether you bought it from Apple or not! This is huge, particularly since you can download songs – and they will start playing before the download finishes – to your mobile iOS devices, and because the files Apple provides are of very high quality (256-Kbps AAC), possibly better quality than the files you have in you library.
Today on my walk around town, when I hit "shuffle" on my iPhone, it chose a random song to play from my entire music collection, which, currently at 53 gigabytes, doesn't even come close to fitting on my iPhone.
Of course this is a natural consequence of both higher wireless bandwidths and higher storage and retrieval capacities of enormous server farms (a.k.a. The Cloud). If your iDevice is always online with cloud computing, then the need for syncing data from your computer to your iDevice has pretty much vanished, if all the data is available on high bandwidth servers.
It's pretty clear to me that the future revenue model of the music industry will be one of subscriptions to stream any music the subscriber desires (or to download with a small fee per track). The artists would receive a certain amount every time their song was streamed or downloaded. This is called the Open Music Model and is just what Spotify does.
For now, at least, to my mind conditioned to the current model of music ownership, iTunes Match is one of the coolest services I've used in a while. It's definitely worth $24.95 of my money every November 15th.