Rdio is the latest competitor in the growing music streaming arena. With Spotify, Pandora, and iHeartRadio all fighting for the top spot, Rdio faces some stiff competition. My first impression was very good.

It was easy to find everything I was looking for. You can link your Facebook account directly to your Rdio account, which adds the feature of following your friends. There are also celebrities and music webzines like Rolling Stone and Pitchfork that can be followed. From there, you go to the main page, which is called "Heavy Rotation." This page shows you everything that everyone you follow has been listening to. The artists that have the most followers are going to be at the top. To the left, there's the Browse page where the standard chart toppers and recent activity pages are located.
Rdio boasts over 20 million songs, so I decided to do a search of three very different artists (Three 6 Mafia, Yeasayer, and DJ Shadow). Most of their music was catalogued so there is a wide variety of music offered. One of the features that is offered is "My Collection" which allows you to take any music you find and add it to a library. You can also make playlists with all of the music you listen to. Spotify offers this same service, but you have to deal with the bombardment of the same three ads every once in a while. Rdio is completely ad free, which made me feel like a kid on Christmas Day. Ads have always been one of those necessary pains with free music services, but with Rdio, you can listen to your playlist of A$AP Rocky, Taylor Swift, and MGMT in peace without getting pressured to get premium services.
In addition to the vast library, Rdio also offers radio services. The stations function like Pandora and Spotify radio, where you select an artist and the service creates a playlist of related artists. One of the cool features is the ability to adjust stations to different levels. For example, the two ends of the spectrums are "Artist Only" and "Adventerous." You can adjust how you want your station to play music. In addition to artist radio, Rdio makes stations based on what your followers listen to, the most recent artists you've listened to, and the music you have in your collection. The radio part of Rdio is ad free.
You can also write reviews for the music you listen to and share your review and a link to the song on Facebook and Twitter. Your friend's recently played songs and playlists are available for you to check out. Rdio is still fairly new so I didn't have a lot of Facebook friends using the service so I wasn't able to follow that many people and I followed a lot of record labels and magazines. However, that can all change and it didn't damper the experience too much, but for those who are into social networking, it may not be as ideal as Spotify due to Spotify's huge popularity.
Rdio also has a mobile app that lets you stream music from your phone. The app is offered on all smartphone operating systems. If you are offline you can play music that you have saved in your collection. Unfortunately, this all comes at a price. The subscription is ten bucks a month for the mobile streaming and offline collection. For college students, there is an option where you can get a subscription for half price. The ten dollar a month subscription fee is pretty much universal, so no advantages there.
Rdio is a solid music service that offers a nice combination of Spotify's vast library and Pandora's power to find related artists. Many features are pretty standard for music streaming services, but Rdio offers a bigger social networking aspect that can grow with time, offering even more variety. The lack of ads gives Rdio's streaming an edge over Spotify's growing space dedicated to advertising. Its really distracting when you're studying to a John Coltrane playlist and a loud, off tempo ad pops up and kills the focus. Rdio is facing a lot of competition but it offers some nice features that give it an edge over its competition. Will it dethrone Spotify? That remains to be seen but Rdio gives Spotify a run for its money.