At a forum in West Hollywood yesterday, Thomas Hesse, the head of Sony BMG's digital music division said that digital sales and service now account for around 20% of the company's music sales – a number that's sure to increase significantly if someone figures out how to sell music that's compatible with all digital music players.
Unfortunately, Hesse also said that Sony BMG's experiment with offering a Jessica Simpson song as an unprotected MP3 was "mostly a promotional play, and not part of a larger strategy," according to Digital Music News, confirming that we're unlikely to see major label music offered in such a way that any device can play it.
One promising development is a new Rhapsody feature that can clone your iTunes library, including purchased tracks, into the Rhapsody format. If every service did this, at least that would provide a semblance of cross-compatibility, and help digital music sales increase faster. (I thought Microsoft was going to try this approach too, but apparently they are not.)
