It’s been about 2 years since the last major iTunes update, iTunes 7, and Apple’s newest installment adds a couple of key new features.

• Visualizer, purchased from the barbarian group, called magnetosphere which simply replaces the old visualizer.
• Genius automated playlist constructor, and Genius Sidebar. I’ll get into detail on these below.
• Album grid view.
• Support for the new iPod Nano 4G, and iPod Touch 2G, etc.

The most interesting of these new features is obviously the genius feature.  The sidebar simply integrates into your library showing tracks that you might be missing or ones you might like based upon what’s currently playing.  The key thing is that it shows songs you might already have a lot, as well as kind of “cliché” suggestions.    Playing “Long Line of Cars” by Cake, gives reccomendations of artists like Beck, Doughtry, The Decemberists and Death Cab for Cutie.   It also has suggestions for other Cake songs which are already in my library that I ripped straight from the CD.

But the Genius playlist constructor is probably the one that’s going to be used the most often and will be what people call the “key feature” of iTunes 8.  Too bad it’s only a version of party shuffle that takes suggestions from what users have bought on the music store.  For instance, I have the Guitar Hero soundtrack, and if I select say, “The Light That Blinds” by Shadows Fall, I’d be expecting a nice mix of hard rock/metal.  But the 25 song playlist Genius returns is filled with songs from Guitar Hero, since the Shadows Fall song is from Guitar Hero II.

I’ve been playing with this feature a lot to try and figure out how it works; I think I’ve figured it out.  It queries the music store for a list of songs purchased by people who purchased the original track.  Genius then finds ones with similar genre, etc, and uses party shuffles algorithm to randomly pick songs from that list that are also in the user’s library.  It is not an algorithm that compares song BPM or waveform.  This is why songs that aren’t on the iTunes Music Store can’t be used.  Apple and bloggers pandering Genius off as though its the next incarnation of Pandora.  Searching Pandora for The Light That Blinds, returns no Guitar Hero related songs, only ones similar in genre, bpm, waveform, etc, or as Pandora states it, “similar musical qualities.”

How iTunes Genius works. Probably.

Apple also gets to collect tons of usage data on everyone who uses Genius, making it a great feature for both users and Apple.  But it would be nice to see an algorithm instead of randomly picking related songs from the iTunes Music Store.   (Note: This is all speculation.)