Mobbler is a Last.fm radio player and scrobbler. If you don’t know what that means, you’re in for a musical treat. And if you do, then Mobbler is definitely for you.

Last.fm is a global online music service that lets you play, discover and share music over the web. The service is free for anyone in the United States, the U.K. or Germany; users elsewhere can try 30 tracks for free, but then must subscribe for 3 euros a month. And Mobbler is a Symbian app that lets you listen to and ‘scrobble’ Last.fm on your Nokia mobile device.

‘Scrobbling’ is an odd term, but it simply means that when you listen to a song, the name of the song is added to your Last.fm music profile. Music in your profile can then be played and shared with others. Users with profiles can also write journal articles about their favourite music, create their own event calendars and invite friends, talk to other users, and form groups around music topics.

Within Last.fm, music is presented in radio-like ‘stations’ that are arranged by musical genre or artist. The idea is this: ‘If you like Song or Artist A, then you might also like Songs or Artists B, C and D.’ For example, launch the Lady GaGa station, and you will be offered music by both familiar names, such as Britney Spears and Rihanna, and lesser-knowns, including Space Cowboy, Jefree Star, and Little Boots. You can then add these songs to your list of favourites (if you like them), ban them from future play (if you don’t), and more.

This video demo from our friends over at The Nokia Blog shows Mobbler in action on the Nokia N85:

Before you can use Mobbler, you will need a new or existing user account on Last.fm. That done, you launch the mobile app, log in with your Last.fm username and password, and then come to this start page:

From here, you can start a new station, resume a station (assuming you have used the service before), search for music, and more.

Below, you can see the results of my search on the Magnetic Fields, a band I like. Up comes ‘Magnetic Fields radio’, and the first selection is ‘Take Me Round Again’ by the Fiery Furnaces:

I like this song, so I tap the heart icon to add it to my favourites. (If I’d hated it, I could have tapped the red-and-white ‘forbidden’ icon to ban the track from future play.) Also, if I had wanted to skip the song, I could have scrolled through the station by tapping the green fast-forward arrows in the lower right-hand of the screen. This would have advanced me to the next song, as many times as I wanted.

Other features include personal lists and a list of recommended tracks based on your previous listening. For example, here’s one of my personal recommendations, a band I’ve never heard of called the Postmarks:

And that’s the real value of both Last.fm and Mobbler – these services expose you to artists and music you might otherwise never have heard of. And because the Last.fm music library is vast, it would take you a very, very long time to exhaust all the possibilities. It is a bit like having the world’s biggest music lover as a friend, recommending songs and artists based on what you like.

In fact, I’ve just scratched the surface of what you can do with Mobbler. There’s an equalizer to adjust the sound on your device. Tools that let you view your Scrobble log, check for updates, set Mobbler as wallpaper, and more. A Search function that lets you find music by song title, album title, artist, or tag. You can also view friends, Mobbler messages in an queue called a Shoutbox, your playlists, recent tracks, events, recommended articles, and more.

On your Nokia device, Mobbler needs 0.29 megabytes of storage and an open Internet connection whenever it is in use. One note of caution: This app is data-intensive — music files are large — so if you have a less-than-great connection, your response times will likely be s-l-o-w. That happened to me a few times, but I found a quick fix by exiting and restarting Mobbler, and also by switching between my operator’s data connection and the Wi-Fi network in my office. Also, with Mobbler moving so much data, if you don’t have an unlimited plan, you could face some extra operator fees.

Fun fact: Mobbler is a beneficiary of Symbian’s Horizon program. Among other things, Horizon helps individual developers publish apps with greater speed and ease. You can learn more about Horizon here.

Mobbler is free to download in Ovi Store. This app has already been downloaded more than 250,000 times, according to Mobbler creator Michael Coffey on his blog . And why not? Mobbler supports 34 languages – including Catalan, Serbian, Latvian and – I’m not kidding — Klingon. That must be music to someone’s ears.