How portable do you like your digital music? Napster (NASDAQ:NAPS) is going all out -- literally -- with the latest version of its music subscription service. Its move to a Web-stored interface means members no longer have to download Napster's software to stream through the 5-million-track library or hit up saved playlists and songs.

It may not seem like a major upgrade -- until you explore the possibilities. Let's say that you're at a friend's house for a party and the DJ doesn't show up. Let's say that you're bored on the road with a company laptop. All you need is a Web browser (just Internet Explorer and Firefox for now) on a PC, Mac, or Linux connection.

Ditching user-installed software for Web-stored applications is fueling the computing craze everywhere. You have Salesforce.com (NYSE:CRM) forcing enterprise software makers to catch up. You have Google's (NASDAQ:GOOG) Google Apps and Adobe's (NASDAQ:ADBE) Buzzword giving Microsoft (NASDAQ:MSFT) a run for its application-software money. Why not music?

Napster's introduction won't be enough to sway the software-tethered iTunes fans from their beloved Apple (NASDAQ:AAPL). However, it does make a Napster subscription more valuable.

Other features in the new Napster platform include preprogrammed genre playlists and a series of music discovery tools that can spit back hours of community-filtered tunes based on a single track preference. Again, that may not be enough to eat away at Apple, satellite radio, or even terrestrial radio, but it certainly adds sticky value to a Napster subscription.

A company like Napster, which is trading for roughly twice the value of the cash on its debt-free balance sheet, is a stock waiting for a catalyst. Is this it? Is this the key to finally catapult the stock out of the single digits?

It doesn't seem that way, but keep an eye on how subscription growth clocks in for the current quarter. If this is a catalyst, you want to catch it early.

Belt out a Foolish tune:

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Longtime Fool contributor Rick Munarriz isn't a subscriber to any digital music service, even though he does have satellite radio. He does not own shares in any of the companies in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.