Pandora Media, Inc. is the operator of Pandora Internet Radio (also referred as Pandora Radio or simply Pandora), an automated music recommendation service and "custodian" of the Music Genome Project available only in the United States. The service plays musical selections similar to song suggestions entered by a user. The user provides positive or negative feedback for songs chosen by the service, which are taken into account for future selections.

While listening, users are offered the ability to buy the songs or albums at various online retailers. Over 400 different musical attributes are considered when selecting the next song. These 400 attributes are combined into larger groups called focus traits. There are 2,000 focus traits. Examples of these are rhythm syncopation, key tonality, vocal harmonies, and displayed instrumental proficiency.

The Pandora media player is based on OpenLaszlo. Pandora can also be accessed through many stand-alone players, such as the Roku DVP (formerly Netflix player), Reciva-based radios (from companies like Grace Digital, Sanyo, and Sangean), Frontier Silicon-based connected audio systems, Slim Devices, and Sonos product(s). On July 11, 2008, Pandora launched a mobile version of their software for the Apple iPhone, iPad, and iPod Touch through the iTunes App Store. Pandora is also available for Android phones,BlackBerry platforms, HP webOS (used on the Palm Pre, Palm Pixi, Palm Pre 2, and HP Veer), and Windows Mobile devices. Pandora was the provider for MSN Radio until MSN discontinued their internet radio service on June 18, 2008. A modified version of Pandora has been made available for Sprint Nextel.

Timothy Brooks Westergren (born December 21, 1965 in Minneapolis, Minnesota), is a co-founder of Pandora Radio.

Timothy Westergren was born on December 21, 1965 in Minneapolis, Minnesota. He graduated from Stanford University with a B.A. in political science. Following his graduation, Westergren spent twenty years working as a record producer and composer (working as a nanny in between jobs), devoting the majority of his time to emerging artists and independent labels.

In 1999 he started Pandora Media along with two co-founders: Will Glaser and Jon Kraft. The Oakland, Calif., company went public in 2011, reporting $138 million in revenue that fiscal year.

As an early project, Westergren and Glaser created the Music Genome Project, a mathematical algorithm to organize music. The idea was marketed by Pandora Media. He along with the other developers patented the Music Genome Project, the software uses a mathematical algorithm to predict a person's musical taste based on a small musical sampling, and is covered by United States Patent No. 7,003,515.