Ever wish there were a radio station that played exactly what you wanted to hear? Well, there is — sort of. Pandora is an online project put together by music experts who’ve spent the past five years analyzing recorded songs from over 10,000 different artists. The analysts have assembled hundreds of musical attributes — or "genes" — into a massive database, which they call the "Music Genome."
To some extent, Pandora can guess what kinds of music you like based on your specific tastes in various musical attributes: melody, harmony, rhythm, instrumentation, orchestration, arrangement, lyrics and so on. You "train" Pandora to refine your selection over time by giving each new song a thumbs-up or -down. While the analysis is very good — nothing yet can beat the human brain of an expert, especially in a relatively subjective realm such as describing music — the system isn’t perfect. If you happen to like one song by an artist, for example, it doesn’t mean you’ll like other songs by that artist, or other versions of the song played by other artists. Pandora sometimes gets stuck on tangents, and it takes some trial and error to get it to move on.
In my case, the music I like generally falls into two broad categories: the great jazz vocalists of the ’50s (Ella Fitzgerald, Nat King Cole) and the folk/rock singer-songwriters of the ’60s and ’70s (Leonard Cohen, Bob Dylan, Paul Simon, The Beatles), with an eclectic mix of various other artists thrown in (Willie Nelson, Chris Isaak, Dave Matthews, Kanye West, Stevie Nicks, Alison Krauss, Fatboy Slim). My musical tastes seem to present something of a challenge to Pandora. A Chris Isaak or a Richie Havens song, for instance, with attributes like "mild rhythmic syncopation," "mixed acoustic and electric instrumentation" and "major key tonality" is characteristically different from a Dinah Washington or Nina Simone song, which features "swing or jazz influences," "a mid-tempo dance style," "strong vocal technique," "a horn ensemble," "acoustic sonority," "interesting part writing" and "strong melodies." (I keep meaning to ask my friend what "extensive vamping" means.) I’ve inputted a number of my favorite songs and artists, and Pandora does seem to be getting the hang of it more and more.
Unfortunately, Pandora doesn’t support classical music yet, probably because most classical pieces are lengthy and linear and therefore not easily described by the relatively simple attributes of popular music.
You can hear a discussion about and a demonstration of Pandora on the December 16, 2005 edition of The Al Franken Show.
Update: Geoff thoroughly explains extensive vamping:
Vamping is essentially the repeating of a section of a song — such as a chorus, verse or (rarely) a bridge — one or more times to create space in the tune. Why would you do this? Maybe to extend a tune out, create space for a couple players to take solos or maybe just because the audience is having fun dancing and it’d be a shame to make them stop. Vamps are sometimes called jams (although jam usually connotes less structure).
Sometimes a vamp happens at the end of a song — say to accommodate a fade-out — but short vamps can easily happen in the middle of tunes. In live performance, bands usually return to the head, main theme or chorus one last time after a vamp before ending a tune. The underlying form is usually dictated by the song, but many elements of a particular vamp are improvised and spontaneous.
Extensive vamping means that the balance of a section or an entire tune is taken up with vamping. For instance, many standards are pretty short songs (often just 32 to 64 bars), so if you hear one of those tunes played for, say, six minutes, that’s a good candidate for the extensive vamping tag. But, basically, extensive vamping can refer to any time a listener thinks, "Oh, the band has gone off on its own now; this isn’t actually part of the tune." Sometimes this can happen in as little as four bars!
By the way, the bit of Pandora lingo that struck me as funny was mild rhythmic syncopation, which is like saying "a mildly woody tree." In music, you can’t have syncopation without rhythm (although you can have rhythm without syncopation).
TidBITS offers a tidbit about Pandora with regard to holiday music.