Music is in the genes

I clicked on an ad for Pandora from my sister's blog. It is an internet radio station created by the Music Genome Project. Users can enter the name of a favorite song or artist and the service plays selections that are similar. According to Wikipedia:

A given song is represented by a vector containing approximately 150 genes. Each gene corresponds to a characteristic of the music, for example, gender of lead vocalist, level of distortion on the electric guitar, type of background vocals, etc. Rock and pop songs have 150 genes, rap songs have 350, and jazz songs have approximately 400. Other genres of music, such as world and classical, have 300-500 genes. The system depends on a sufficient number of genes to render useful results. Each gene is a number between 1 and 5. Fractional values are allowed but are limited to half integers. (The term genome is borrowed from genetics.)
Given the vector of one or more songs, a list of other similar songs is constructed using some distance function.
To create a song's genome, it is analyzed by a musician in a process that takes 20 to 30 minutes per song. Each gene is rated on a scale of 1 to 5. Ten percent of songs are analyzed by more than one technician to ensure conformity with the standards, i.e., reliability.

It is only available in the U.S. due to licensing issues.