This Pandora's box is filled with music. The Internet radio station generates playlists based on a user's favorite artist or song. As part of the company's Music Genome Project, songs are analyzed according to musical features -- including details of instrumentation, harmony, lyrics, melody, rhythm, and vocals. Users enter the name of a song, and Pandora creates a playlist of songs with similar characteristics. Pandora's service, free to its more than 175 million registered users and available only in the US, is supported by local and national advertising. Chief strategy officer Tim Westergren founded the company in 2000; Pandora went public in 2011.