What Facebook is proposing is to throw its significant user base at the problem. Instead of asking a friend to go out of their way to view your playlist on a music service's website or follow a link that you've tweeted, emailed, or texted, they can simply visit your wall, take a gander at what you're listening to, and click. If they're not subscribed to a particular service, they'll likely be offered the opportunity to join or take the service for a trial spin. Do that and not only can you listen to the streaming music, but you can open a chat window to talk about it with your friend.

This is, of course, a potentially enormous boon for music streaming services. More than anything that's been tried before, this will tempt a lot of people to try one of these services. If the experience is transparent and the price of entry not too painful, it could significantly shift people's attitudes about "renting" music.

And that could be an interesting challenge for Apple and other services that sell music. If you can have access to virtually anything ever recorded (and you put little thought into what that access costs over time), there's less motivation to own music. Apple's , while cloud-based, doesn't address this issue because it works only with music that you own.

Of course Apple may have plans to get into the subscription game as well. It has the contacts and catalog, it certainly has the means of delivery, and it has control of the most popular portable music players on the planet. Given that, it could trump Facebook's efforts, which, at this early date, look a little clumsy given that they're tied to a browser. But, up to this point, Apple hasn't strayed from its "People want to own their music" stance.