Rdio is a monthly subscription service where you can listen to and download unlimited music, create playlists, follow lists of other users, and share them through social media. I've been trying a free membership for the last few weeks and I'm totally addicted. If you are a fan of Skype, these are the same creators so it's a really simple user interface.

What I like best about Rdio is it's a really cheap way to listen to music. A basic membership is $5 a month and there is no limit to what you can listen to. I definitely spend more than $60 a year downloading albums from iTunes. With a membership like this, while you can purchase the albums you like, you don't necessarily need to since you can listen to them at any time. I also think it's really cool how you can see what your friends are listening to and listen to it yourself. You can listen on any device and download albums for the duration of your membership.

If, like me you think that letting people see what you listen to is the equivalent of being seen in your underwear, (yes I'm in my 30s and I do listen to Justin Bieber) you can mark your collections as private.

There really is no downside to the service. I haven't encountered any buffering and I love that you can listen to entire albums rather than purchasing it and finding out after that the preview from iTunes made it sound way better than it was.

From a usability perspective it would be nice to be able to search by genre and I think the design is so simple that some of the functionality is hidden but anyone can use this and I think this will become huge.