Rdio Rounds Up More Cash for Online Music

No one has figured out how to make online music subscriptions really work, but people are still trying: Rdio has raised a new $17.5 million round led by Mangrove Capital. The company had previously raised at least $6 million from Skype and its founders; the new dollars are supposed to help it compete with Apple’s iTunes and a host of other subscription services, including Spotify, Rhapsody and MOG.