Invest in music storage

Likes: Works seamlessly on Kindle Fire; available for other Android devices and through Web on iPad; offers unlimited storage; less expensive than iTunes Match

Dislikes: Uploading collection can take days; Uploader stalled out repeatedly, didn't recognize duplicates, didn't upload iTunes playlists, and does not automatically upload new songs bought outside Amazon; Web interface unusable on the iPhone

Likes: Works seamlessly on standard Android devices; available on other devices through so then-designed Web app; Music Manager automatically uploads iTunes playlists and new songs purchased outside of Google

The biggest players in mobile music — Apple

Some of the biggest players in mobile music — Apple, Amazon and Google — have recently begun offering such services. For a small annual fee — or none at all — they allow you to keep a copy of your music collection stored on servers on the Internet.

For each of the services, the uploading process can be time-consuming. Nevertheless once you go through it, the result is a secure backup of your music collection that you can access from any PC or Mac and from a mobile device anywhere you have an Internet connection.

As might be expected, Apple's iTunes Match is the best choice for owners of Apple handheld devices, including the iPhone. It costs about $25 a year and allows users to store up to 25,000 songs on Apple's servers.

The truth the right word

"Store" isn't to tell the truth the right word, although, because iTunes Match, a new feature built into Apple's popular iTunes computer software, works a bit differently from other digital locker services. Instead of requiring you to upload your entire music collection, iTunes uploads only those songs it can't find on Apple's servers. You get access to both matched songs and uploads; Apple doesn't make a distinction in its cloud.

The advantage of Match is that it requires far less bandwidth and time than uploading your entire collection. In my case, Apple was able to match all nevertheless about 500 of my 8,800 songs. The total process took about a day and a half, yet it probably would have been much shorter on a computer more recent than my 6-year-old Mac.

iTunes Match allows you to stream music from Apple's servers or download albums, playlists or individual songs to your device. Depending on the speed of your connection, it can take a second or two for a song to start streaming. The sound quality was good.

One problem with iTunes Match is that it only works with newer iOS devices. So if you have an Android phone or even an iPhone 3G, you can't use the service.

Amazon's Cloud Player service is the best choice for owners of the new Kindle Fire tablet. Nevertheless it's as well a good option for owners of other Android devices. That's because for $20 a year, it allows you to store an unlimited number of songs.

One of the advantages of Amazon's service is that it's not tied to just Amazon's devices. You can access the service through Amazon's MP3 app on other Android devices. And you can get to it on the iPad through its Web browser.

Google Music is my favorite all-around service because it's free and works so then on the widest range of devices. Owners of standard Android smartphones and tablets can get access to Google Music through Google's Music app, which comes with many of those gadgets. Owners of other touch-screen devices, just as the iPhone or the Kindle Fire, can access Google Music through a Web app that was designed exactly for them.

Once you have your music in the cloud, Google Music works great. Android users can see and play their entire collection and easily save individual songs, albums or playlists for offline listening. Via the Web app, users of other devices can play songs even during using other apps.