Even before today you could listen to full-length tracks as part of a "similar artists" radio station, just not on-demand. And other aspects of the site, like seeing who else is listening to your music, recording ("scrobbling") tracks you listen to in iTunes, and offering user-editable information about the artists, were already cool and continue to be so.
If you sign up, please add me as a friend; I'm funcrunch as always.
