There's an article about it at Slate. Here's a sample:
...bringing the rigor of science to the study of the pop song is precisely what a California technology company called Savage Beast has done. The name of their project, The Music Genome Project, speaks to its outsized ambitions: The company touts it as "the most sophisticated taxonomy of musical information ever collected on this scale." Sounds great, but does it actually work?
Employing an army of rigorously trained music analysts, most with degrees in music theory, Savage Beast has dissected "the vast majority" of music that has appeared on the Billboard Music Charts since the mid-1950s, as well as large swaths of jazz and indie rock. Each song has been coded according to a proprietary list of 400 music attributes. Some, like "rhythm" and "tempo," are obvious to the lay listener; others, like "degree of chromatic harmony," are more complex, and, well, pretty much require a degree in music theory to explain. The point of all this fuss is to produce the ultimate music recommendation system, a system that's not based on the flimsy criteria that people normally use—popularity, genre, hipness, how the lead singer looks in tight jeans—but on precisely defined musical characteristics.
As novel (and quixotic) as all this sounds, it isn't even the first time a codification of music has been attempted. The Music Genome bears a striking resemblance to another, much older project begun by the famed musicologist Alan Lomax in the 1960s. Lomax, best known for recording and popularizing the likes of Leadbelly, Muddy Waters, Woody Guthrie, Mississippi Fred McDowell, and Jelly Roll Morton, dedicated the last 30 years of his career (he died in 2002) to an elaborate, lofty, and ultimately unfinished project called the Global Jukebox.
Like the Music Genome, the Global Jukebox is based on a music notation system. Lomax called his "cantometrics," a made-up word he defined as meaning "song as a measure of society." It consisted of 36 parameters that could be used to compare musical performance styles across cultures. And, just as the Music Genome would, Lomax employed an army of rigorously trained research assistants to code and input thousands of songs into a central database. There are 4,400 in all, spanning 400 cultures, everything from Pygmy recordings to American pop tunes. This is only a portion of what Lomax intended. A series of strokes in the 1990s prevented him from getting the Jukebox past the prototype stage.
The whole article is worth a read. I think a new recommendation system sounds great, especially if it means my not having to skip Depeche Mode every fourth song on "my" internet radio station at Yahoo!.