San Francisco - Social music service Rdio on Tuesday announced its official launch, offering unlimited streaming of a library of seven million songs to the desktop and smartphones for $9.99 per month. A Web-only version of the service will cost $4.99 per month, while subscribers will also be able to purchase tracks a la carte for an average price of 99 cents.

San Francisco-based Rdio was founded by Skype and Kazaa creators Janus Friis and Niklas Zennstrom, and is funded by Atomico.

The company has licensed tracks from all four major labels, in addition to independent aggregators including IODA, IRIS, Finetunes, INgrooves and The Orchard.

The mobile version of the company’s service works with Android, BlackBerry and iPhone platforms, and features caching of songs for offline playback.

Users can automatically match music from their iTunes or Windows Media Player libraries on Rdio, "follow" friends to discover new music, and create and listen to collaborative playlists.

Related Links:

http://tinyurl.com/39xynsa

http://www.rdio.com