iCloud arrived alongside iOS 5 and the iPhone 4S last month, but music lovers had to wait just a bit longer to spin their virtual platters via iTunes Match, Apple’s “one more thing” announced at WWDC 2011 back in June and now, finally available for anyone willing to part with $24.99 each year. Curious about how it works and why you might want it? Read on!

iTunes Match isn’t strictly a component of iCloud -- after all, it requires an annual subscription payment of $24.99 and tracks you upload to Apple’s servers don’t count against your free 5GB storage allotment. In fact, you don’t even need iCloud at all to use it -- the service works through the same Apple ID used for iTunes purchases. Otherwise, the only requirements are iOS 5 on your mobile device(s) and the latest version of iTunes, currently 10.5.1.

Why iTunes Match?

Music lovers have plenty of choices these days, including paying upwards of $10 per month for services such as Spotify, which allow you to stream pretty much whatever you want, including content matched from your iTunes library -- assuming it already exists on their servers, that is. iTunes Match does a similar trick with content stored on Apple’s servers, but it’s not a streaming service (contrary to early rumors that it was) but rather a “scan and match” download service.

The concept is simple: Subscribe to iTunes Match for $24.99 per year via iTunes (you can’t do it on your mobile device), turn it on via the Store menu and the software will scan your music library, upload the results to Apple and then match them against the company’s library of more than 20 million available songs in the iTunes Store. Matched tracks then appear on any computer or device where you’ve activated iTunes Match, and anything not matched gets uploaded so it’s likewise available.

How Does It Work?

Apple hasn’t specifically said what technology is behind iTunes Match, but it’s widely assumed they’re using the Gracenote library for most of the heavy lifting -- the same database used when you insert an audio CD into iTunes and the artist and track information magically appears. There’s clearly some other “fingerprinting” that goes on behind the scenes, but knowing Apple, they may never let us peek through the veil.

After doing a scan and match followed by uploading tracks that couldn’t be identified, your entire music library will now be available from any of your computers running iTunes or iOS 5 devices where iTunes Match is turned on. (You’ll see a fluffy little cloud icon next to the Music sidebar entry of the desktop iTunes.) Now, you’ll see a complete duplicate of your library on another Mac with iTunes at all times, and download individual tracks or even entire albums, artists or playlists whenever you’d like.

The 256Kbps Advantage

Perhaps the biggest advantage of iTunes Match over the competition is that it allows you to actually download 256Kbps AAC DRM-free tracks from the iTunes Store, regardless of whether they were purchased from there. That means lower quality copies, old MP3 rips from CDs or even tracks you downloaded through more scrupulous means (BitTorrent, files from friends, et al) can be replaced with the highest quality copy available from iTunes -- with the complete blessing of Apple and the music labels, who are presumably sharing a cut of that $24.99 each year for their cooperation.

However, there are a few caveats. For one, tracks won’t magically get replaced once you turn on iTunes Match -- you’ll first have to delete the original files from your main Music playlist in iTunes, where they’ll magically reappear again, but with a small cloud icon next to them. Click on the icon to download the track (or album, or playlist) and you’re likely to get the promised 256Kbps AAC DRM-free goodness -- but maybe not.

iTunes Match “Gotchas”

Developers who have been beta testing iTunes Match prior to its release gave mixed reports about how well the service actually matched their music, with many users forced to upload the majority of their music when the bulk of their library didn’t get matched. In those cases, you’ll get back what you put in -- the old “garbage in, garbage out” philosophy, as it were. If you have a lot of unmatched tracks of questionable quality, they will get downloaded from iTunes Match exactly the same way.

To see which tracks have been matched by iTunes, go to View > View Options and check "iCloud Status." Now you'll see a column that displays "Purchased" for tracks you've bought via iTunes, "Matched" for tracks that iTunes Match successfully matched and "Uploaded" for tracks that couldn't be matched and had to be pushed up to iCloud instead. You can also view these tracks by using Command-I and clicking on the Summary tab, as shown above. If you happen to have a second Mac handy, adding it to iTunes Match will make your entire library available there also.

Finally, there appears to be some bugs lurking in the machine. Our Smart Playlists no longer display properly, with tracks tossed helter skelter throughout unless we turn off Live Updating (available via Edit Smart Playlist). Our main iTunes library seemed to keep things arranged properly, but they show up in random order on a second Mac as well as through the Music app on our iOS 5 devices.

iTunes Match in iOS 5

Speaking of which, things are a bit easier when it comes to iPhones, iPads and iPod touches running iOS 5. Browse to Settings > Music and you’ll now find an option to turn on iTunes Match at the top. Once you’ve done this, a second option called “Show All Music” will also appear. If you’d rather view only the tracks you’ve downloaded to that particular device, you can switch this to off.

Otherwise, a trip to the Music app will start populating the screen with all of your playlists, songs, artists and albums, just like magic. In fact, visiting Settings > General > About will even show an impossibly high number of songs available, even though you haven’t downloaded anything yet. (This won’t change, even if you switch off “Show All Music.”)

Needless to say, this is a godsend for owners of smaller capacity devices, such as one of the repriced $99 8GB iPhone 4 models. With iTunes Match, you can download only the tracks you want to hear, as you need them, rather than taking up space on the device when you don’t. Now that playlists can be created and edited via the iOS 5 Music app, syncing your music from iTunes may no longer be necessary.

Unfortunately, right now iTunes Match is an all or nothing proposition -- once you flip the switch and tap Enable, any music synced to that device from iTunes will be wiped and replaced with cloud-based iTunes Match metadata. Sadly, you don’t have the option to sync certain tracks or playlists and then use iTunes Match to access the rest as needed -- you’ll have to choose one or the other, then download iTunes Match tracks yet again should you later need to restore or change devices.

Is iTunes Match Worth It?

$24.99 per year is quite a modest sum for most of us, especially compared to streaming music services like the aforementioned Spotify at $10 per month (there’s no discount for an annual payment, either). iTunes Match works out to a mere seven cents per day (compared to Spotify at 33 cents a day) to make your entire music library available from all of your devices, which sounds like a real bargain. However, taking advantage of iTunes Match means ponying up that $24.99 every year -- once you cancel the subscription, you’re back in the Stone Ages, again syncing via iTunes.

But what about all of those high-quality 256Kbps AAC DRM-free iTunes Match tracks you downloaded? Apple isn’t really saying, but it appears they’re yours to keep forevermore, even after the subscription ends. That means you could realistically sign up for one year, delete your low-quality tracks after they’re scanned and matched, then pull the high-quality versions back down and everyone’s happy (especially you!). Clearly Apple is hoping you’ll stick with them for the long haul, but from what we can tell, they haven’t thrown up any road blocks to prevent this type of use (or abuse, depending on how you look at it).

Of course, we’re hoping that the current implementation of iTunes Match is just the opening act -- if Apple can actually implement truly streaming tracks in the same manner, that $24.99 per year would look like an even better bargain, especially if the scan and match technology continues to improve.

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