Rdio is opening up its social music service to a new round of users, the company said in a blog post on Wednesday.
The service, created by Kazaa and Skype founders Janus Friis and Niklas Zennstr
Users who have helped develop the service have been sent invitations which they can pass on to their friends.
Rdio has also been integrated with social networks, so users can share links to music via Twitter and Facebook. Listening to the music requires a subscription: Invited users can choose between Rdio Unlimited, which costs US$9.99 per month and works on the Web and some smartphones, and Rdio Web, which is web-only and costs $4.99 per month.
At first, the service will only be available in the U.S., but other parts of the world will follow in the near future, according to the blog post.
Friis and Zennstr
However, Rdio has independent labels and music majors such as Warner Music on its side, the blog post said. A version of the Rdio content partners page cached by Google on April 27 also listed EMI Music and two distributors of independent music, The Orchard and Isolation Network, which trades under the name INgrooves. That page is no longer accessible.
Rdio is far from the only service that offers streaming music to mobile phones. Others include the European service Spotify, which so far isn't available in the U.S. Spotify offers a subscription-based service and an ad-funded version that is free to the user. The latter has been a runaway success, but Spotify has had problems converting people to the paid version, according to Paolo Pescatore, an analyst at CCS Insight. Users are willing to pay for tracks and albums, but they haven't been as keen to pay for monthly subscriptions, he said.
Kazaa and Skype were both big hits. But one of Friis' and Zennstr