2011 is shaping up to be a big year for the world of digital music. Apple recently confirmed rumors of a new subscription service in the works for iTunes, while Google announced plans to release its own hybrid digital download store/subscription–based music locker. In addition, Spotify — one of the most highly anticipated subscription services — finally plans to launch in the United States this year after experiencing overwhelming success in Europe. There’s certainly a lot to look forward to, but that doesn’t mean you should refrain from experimenting with currently offered music subscription sites. If you’re a music enthusiast looking to explore content beyond your own iTunes library or CD collection, then do yourself a favor and give one (or all) of these services a try.

Grooveshark Basic – Free Grooveshark Plus – $6/month Grooveshark Anywhere – $10/month

Grooveshark provides the easiest and most diversified listening experience of all the tested sites. Thanks to a largely clutter–free layout (save for one side bar advert) and a quick, proficient search engine, finding your desired listening material is a cinch. Upgrading to the Plus subscription removes all advertisements, while the premium “Grooveshark Anywhere” grants you mobile access and offline storage. Grooveshark’s music database is composed primarily of user–uploaded files, so it’s not uncommon to come across bootleg remixes or rare live tracks — a perk that eludes most other streaming sites. At the same time, building a library of user uploads makes for the increased possibility of pesky duplicate tracks, and also detracts from the site’s ability to ensure high–quality audio.

Rhapsody Premier – $9.99/month Rhapsody Premier Plus – $14.99/month

Having been one of the earliest players in the on–demand music scene, Rhapsody now offers the largest online music database. For $9.99/month, you get access to Rhapsody’s library of over 10 million songs, as well as the ability to access and stream Rhapsody from your mobile device ($14.99/month gives you the added benefit of streaming from up to three devices). The site also boasts a great selection of radio channels and user playlists, all of which can be streamed and stored on mobile devices. The catch: all of Rhapsody’s audio files are encrypted with DRM protection, meaning that once the subscription is cancelled, you are unable to play back any of the downloaded tracks.

Basic – $4.99/month Primo – $9.99/month

MOG proved to have the most user–friendly interface of all the subscription sites, and was also the most fun to use. The site includes a social networking feature (similar to iTunes’ Ping) to help you share and discover new music with fellow MOGers, and also contains a pop–out miniplayer that builds playlists for uninterrupted streaming. You can dictate the content of the playlist with an interactive sliding scale that allows you to shift between a single artist or multiple artists of similar styles. A basic subscription provides you with web-streaming access to MOG’s library of over seven million songs, while a premium plan gives you the additional benefit of mobile access and offline storage. The biggest letdown: while MOG’s web–based service is highly innovative and enjoyable to use, their mobile application is not up to par with some of the other competing streaming apps.

RDio Web – $4.99/month RDio Unlimited – $9.99/month

A fairly recent entry in the digital music sphere, RDio seems to be most concerned with the social networking aspect of streaming services. While you are still given the option of browsing through a standardized music catalogue, RDio places a greater emphasis on finding music through the listening history of other members and “influencers.” Like Twitter, the homepage displays a list of active users along with some of their current listening statistics and a record of any playlists they have created. While some might find this approach a helpful way to discover new music, others who opt for a more artist–centric approach to music would be better off with another service.

Final Thoughts

* Best Streaming Experience: MOG * Largest Catalogue Selection: Rhapsody * Best Offline Availability: RDio * Greatest Ease of Use: Grooveshark