What would happen if you took your favorite streaming music service and mixed in a hefty dash of Facebook? It would probably look a whole lot like Rdio (free; paid services start at $5/month).

When you select folks to follow, you can see what tunes they're listening to and you can browse any playlists they've created. Or you can skip the whole social aspect and jump right to browsing through available music, which is organized into New Releases, Top Charts, and Recommendations, which are created for you based on your listening habits. In addition, you can search for an artist, song, or album. My biggest complaint about Rdio is that sometimes it took too many clicks to actually begin playing a song; often, I had to click an extra link or two after the point I'd expected the music to begin playing.

Rdio's social features do make it easy to find new music by following other users, but this capability wasn't quite as useful as I expected. I went looking for new workout music, but found it difficult to find users who might have playlists I'd like. That's because playlists can have any title, and when I see a collection called "Thursday Night Mix," it's hard to know whether that might include any titles that will keep me going while I'm on the treadmill.

I also found Rdio's free version very limited. This option was added to the service recently, likely to keep Rdio competitive with its high-profile rival Spotify, which also offers a free version. While Rdio's free version does have the benefit of being ad-free, it's also limited--and the extent of those limits aren't entirely clear. While Rdio limits how much music you can listen to when using a free account, it doesn't set specific limits. Instead, the company considers usage of free accounts on a per-user basis, and displays the usage in a meter that is visible to that specific user. Spotify, meanwhile, sets a standard limit on its free accounts.

Rdio's paid versions start at $5 for a basic Web version that offers unlimited streaming from a Web browser or Rdio's desktop application. An unlimited account, which costs $10 a month, adds the ability to use Rdio on a mobile device. An unlimited family account, which includes two unlimited subscriptions, costs $18 a month.

Rdio offers a lot to like. It has a vast music library, delivers impressive music quality, and is easy to use when you're on the go. I do wish its navigation were a bit more intuitive: As a music service, Rdio should make it much easier to get the music playing.

Note: This link takes you to the vendor's site, where you can sign up for the service.

--Liane Cassavoy