According to ZDNet "Yahoo recently debuted a beta version of its audio search engine, available at audio.search.yahoo.com. The engine carries an index of over 50 million tracks, and retrieves results from leading stores like iTunes, Rhapsody, MSN Music and Napster. The service also offers a wide range of non-musical files, including podcasts. The engine is designed to be first stop for a wide range of digital music searches, and could help Yahoo increase its overall search engine audience."
"While Yahoo lists results from a long list of digital music stores, the Yahoo Music Unlimited service gets top billing…Listings for 7 other digital music services are revealed after the track title is clicked. For users that want to review their options, Yahoo helps to sift through varying price points, codecs, and even provides direct download links. Clicking an iTunes Music Store download link, for example, spawns the iTunes application and directs the user
to the proper download. That type of referral is extremely valuable, and could raise overall volume on paid downloads and subscriptions considerably. But those increases could come at a cost for digital music stores, with Yahoo potentially disrupting carefully cultivated customer relationships."
