may some music be legal to dowload after all?

I ran across some articles which mention a few artists that actively promote the swapping of their music. Obviously, I am interested in this. My first thought was, "This is too good to be true...how can they promote free acquisition of their product?" My second thought was, "Wait. Dave Matthews and John Mayer don't even own their own music; they're not speaking for the record companies who actually do."

So now what? Did I get my hopes up for nothing? I'm gonna research this a little more...