Pandora is an online music streaming service that offers personalized radio stations based on users' musical preferences. It was founded in 2000 by Tim Westergren, Jon Kraft, and Will Glaser, and it quickly gained popularity for its unique approach to music discovery.

The core feature of Pandora is its Music Genome Project, which analyzes the characteristics of songs, such as melody, harmony, rhythm, instrumentation, lyrics, and more. Based on these attributes, Pandora creates personalized radio stations tailored to each user's tastes. Users can provide feedback by thumbs-up or thumbs-down on songs played, allowing Pandora to refine its recommendations further.

The Music Genome Project, however, is the underlying technology that powers Pandora's recommendation system. It is a sophisticated music classification system that analyzes songs based on a multitude of attributes, including melody, harmony, rhythm, instrumentation, lyrics, and more.

Each song in Pandora's vast library is manually analyzed by trained musicologists who assign "genes" or attributes to describe its characteristics. This detailed analysis allows Pandora to understand the musical qualities of songs and create personalized radio stations for users based on their preferences.