Do you have digital baggage? Apple wants to help...again. Apple's iTunes Match service, which went live in iTunes 10.5.1 Thursday and costs $24.99 a year, tackles a problem users run into as time goes on: music libraries continue to grow, as do the ways users want to listen to their music, but there's still the pesky issue of where to store that library of songs, and keep it safe. Streaming music services like Spotify and Rdio have solved this by pushing the library and purchase mode to the back seat, offering monthly paid subscriptions instead. The end result fixes two problems: first, you don't have to worry about what content you have and don't have, and second, it's device- and storage-agnostic, because you can just stream what you want. But such products aren't dealing with the kind of baggage iTunes users might have, which could be gigabytes upon gigabytes of music tracks purchased legitimately, right alongside music that was taken from a friend or pulled from a peer-to-peer service. If those tracks aren't in the service's collection, you're out of luck. You're forced into continuing to hoard them on a machine, even taking that library (and subsequent digital baggage) with you from computer to computer for the rest of time. Complicating that further is Apple's own lineup of devices that tap into iTunes, which play by different rules. There are computers with plenty of storage and big screens to manage the equally large music libraries. One step below that are iOS devices like the iPhone, iPod Touch, and iPad, which pack considerably less storage than a computer, but are where listening to music on the go is equally, if not more important, given their mobility. Finally, there's Apple TV, the diminutive $99 box that acts as a conduit to the iTunes Store for movies and TV shows but that so far has relied mostly on networked music libraries and streaming radio stations for any musical ability. Trying to maintain a single library between all these is not impossible, but it can present challenges. With the introduction of iCloud in June, Apple began to solve at least one part of the problem, offering users a way to re-download tracks they've purchased from the company on any device--be it a computer running iTunes, or an iOS device. The previous system would require that users hoard that digital file somewhere for safe keeping. iTunes Match also takes on the licensing issue that surrounds the rest of the user's library--the music that person didn't buy from Apple--up to 25,000 tracks of it. This is especially relevant given where Apple's iTunes started out. Between when it was released and when Apple launched its Music Store, the company's tag line was "Rip. Mix. Burn," an encouragement to grab music tracks from CDs and hoard them in libraries. iTunes Match addresses the hoarding problem by finding user tracks that correspond with what Apple has in its library, and giving users a licensed copy, digital safe-keeping of unmatched tracks, and a way to re-download either of those to any device. This, in itself, is one of the biggest adjustments in the way Apple is rethinking storage. No longer is it about saving those files to a hard drive for safe keeping. Instead, you're paying for a highly specialized storage service that keeps everything, even tracks that weren't in Apple's library, in the cloud. In many ways, the service hearkens back to MobileMe, Apple's precursor to iCloud, on which iTunes Match relies. The original pitch for MobileMe was a "(Microsoft) Exchange for the rest of us," offering users a way to keep files, settings, and contacts flowing between devices, as long as you were paying the annual fee. Just like Match, it too did much of the heavy lifting on Apple's servers in return for staying within Apple's system. But MobileMe tried to do too much, too fast, and suffered numerous hiccups on its way to stability and utility. This time around, Apple seems to have learned from that lesson, pricing Match at a fourth of what MobileMe cost and keeping its utility far more specialized. Where MobileMe sought to mix a variety of services together into one, Match is simply a piece of iTunes and iCloud that aims to simplify a particular behavior. That sounds pretty simple. Let's hope that means better performance.