For those who don't want to read the article, here's the gist. We're releasing our song authoring tools to the general public so you can author your band's songs for Rock Band. You need to have the rights to the songs, so what you won't be seeing is five hundred versions of Stairway to Heaven. But basically, you'll use the full set of authoring tools that our audio department uses to make tracks for the game, author the song on the computer (using your master recordings), and then upload them to the community for peer review. If your song doesn't break copyright, and passes muster for playability and content (swears are bad, kids), then it gets uploaded to Xbox Live, and you can set a price for the song. Anyone with Rock Band can buy it, and you get 30% of all the sales.
Why is this awesome? Because it allows a ton of small, unsigned, indie, etc bands access to the platform. They can take it upon themselves to use it as a marketing tool, or just use it to get a bunch of free exposure to a huge audience.
Basically, it's a really cool opportunity for a lot of smaller artists to get involved and get their music out into the world. And it's way better than MySpace.