Facebook just became a better place for musicians to share their music, as the service has just launched a “Listen” button with prominent placement on musician pages.

It looked like Spotify was the service of choice when I first checked out this feature, but it appears that Facebook will automatically fire up the music service that you use the most. This is going to be a huge boon for services like Spotify and Rdio, which are already seeing a lift from Timeline and real-time listening links in Facebook Ticker.

Here’s what the Listen button looks like when you visit a prominent musician’s page on Facebook now:

15 Gotye 520x226 Facebook launches Listen button using your favorite music service on musicians pages

When you hover over the Listen button you’re told that this feature, in my case, requires Spotify, and once clicked a modal pops up prompting you to launch the music service’s app:

15 Gotye 2 Facebook launches Listen button using your favorite music service on musicians pages

15 Gotye 1 520x248 Facebook launches Listen button using your favorite music service on musicians pages

This is the type of feature that makes Facebook the perfect place to browse for new artists, as when you see that your friend has liked a band that you haven’t heard of, you can immediately listen to some of their tracks.

This is exactly why a service like Spotify combined with Facebook is Apple’s worst nightmare. Not only does this give people more of a reason to stay on Facebook, it completely changes the way that people explore music. It’s also a feature that MySpace saw massive success with in its early days.