One of the new features of iTune 8 is the "Genius Playlist."
"Play a song, click the Genius button, and iTunes creates a playlist of other songs from your library that go great together. "
I've played with it a little bit, but not a whole lot yet.
The options are these: (1) Limit list to 25, 50, 75, or 100 songs; and (2) If you don't like something about the playlist it produces, there's a "Refresh" button that gives you a new list.
So far, I've noticed a few things:
(1) It sometimes fixates on a handful of songs. For example, I created a "Genius" list based on Alison Moyet's song, "Dorothy." It produced a list that included Duffy's "Mercy" second on the list and Fratellis' "Mistress Mabel" third. I refreshed the list five times, and "Mercy" and "Mistress Mabel" did not move from second and third place.
(2) It sometimes produces bizarre juxtapositions, such as following Cake's cover of "I Will Survive" with Placebo's cover of "Running Up That Hill." Both songs were chosen as follow-ups to "Fidelity" by Regina Spektor. It can produce some reasonably decent playlists, but when it goes wrong, it goes stunningly wrong.
(3) Albums for which "This song does not have enough related songs to create a Genius Playlist" include Kate Bush's "This Woman's Work" (a B-sides and rarities collection only available in a box set ten years ago), David Byrne and Brian Eno's new album, "Everything That Happens Will Happen Today," "Infinite Joy," "Spring Awakening" cast recording (in fact, all cast recordings in general), and anything that I've encoded but given a new album title to. It cannot create Genius Playlists from these songs, yet it has no trouble incorporating these songs into other playlists. So when it uses these songs in other lists, on what does it base this? Artist name? An assumption about the era or genre based on who the artist is (e.g., assuming that David Byrne songs must be from the 1980s)?
(4) In the long run, it seems to be just as effective as "Shuffle" for randomizing music. Maybe even better, in that with "Genius" lists there's a greater possibility that the next song might actually fit well with the song you're listening to.
Overall verdict: Not bad. Not great. Useful, but far from necessary.