Simply put, Smart DJ uses smart clustering algorithms using user generated play data as well as music metadata to deliver a Pandora-esque feature set. I lead the project from inception to shipping. It was exhilirating seeing the feature come together, from a deep tech algorithm perspective as well as from the interaction design and visual design perspective. I learnt a lot about design innovation, interaction design, marketing and brand identity. We earned 2 patents for this project.
Within the Zune PC software, my favorite surprise was the Smart DJ feature, which sets up an endlessly rotating playlist based on a particular song or artist. Like a lot of other Zune features, it works best if you've got a Zune Pass (which costs $14.99 a month)--in this case, it'll rotate not only through songs in your collection but also through the millions of songs in the Zune Marketplace, delivering the same kinds of surprises that Pandora fans have grown to love. If you don't have the Zune Pass, it simply draws songs from your collection, similar to how iTunes Genius works (in this case, Marketplace songs are greyed out but clickable if you want to buy them).
Also available from Quickplay is one of the most dynamic new features, Smart DJ Mixes. Search for an artist in one of the five Smart DJ Mix boxes to create a dynamic selection of 30 tracks, culled from either the Marketplace or your collection, that blends your chosen artist's music with that of "related" artists or albums and changes every time you play the mix. Yes, this is remarkably similar to iTunes' new Genius Mixes (which are only catch-up to features Rhapsody has had for ages), but it's long overdue and well in keeping with the Zune's "Join the Social" aesthetic.