This week’s mission: A beginner’s rundown of four major Internet music streaming services: LAST.FM, GROOVESHARK, SLACKER and PANDORA.

Without further ado…

1. LAST.FM

Going in, I was already a big fan of last.fm, and that’s because I scrobble. No, it’s not as filthy as it sounds. To scrobble means that you let the last.fm service track the music you play on your computer or portable device, linking you to others who do the same, with comparisons of your tastes and suggested artists to check out. It’s beautiful in its simplicity.

There are even (unofficial) ways to scrobble data to last.fm from other services like Slacker and Pandora, should you care to. Well-played, last.fm. Well-played.

While revealing of your true self in the same way a Facebook drunk picture can be (Do I really listen to Corey Hart that much? you’ll ask yourself), it’s the scrobbles that give last.fm its power. No other site can match last.fm’s ability to unite fans of the most obscure possible acts from all over the globe. It’s a treasure trove of the underground, the underrated, the undiscovered and the antiquated.

I’ve been a last.fm user for almost three years, in which time I’ve scrobbled about 50,000 tracks from about 2,000 different artists, many discovered through the site itself. But I never touched their subscription radio feature even once, until so recently. I suppose the prospect of making a decision based on thirty entire tracks just wasn’t worth the bother. Thirty tracks on last.fm represents a couple hours of listening, at best. Costco booths give you bigger free samples than that!

But for purposes of this article, I listened. And I was exposed to roughly thirty awesome artists I’d never heard of before. Impressive, but not surprising considering what I know of last.fm Unlike the ‘listen to related artists’ features of other sites — dictated from the top down, by genre marketeers — last.fm’s choices of related artists are generated by the scrobbles of other users. And other users aren’t DJs. They don’t care about flow. They can be eccentric and eclectic. And they can surprise you in the best way.

And… now I’m out of tracks. Luckily, last.fm’s subscription service is very cheap (as advertised, it’s only $3.00 a month). Of all the pay services listed here, last.fm’s is the one I’m most likely to embrace. Call it brand loyalty, but the price is right, the interface is a breeze, and the musical selection is so far off the scale that they’ll have to start measuring in parsecs.

A related note: Where clunky old Myspace claims to be the arbiter of undiscovered basement bands and quirky DIY auteurs, last.fm actually provides, and then some. Take note, unsigned musicians — if you’re not on Last.fm, you’re nowhere. Perhaps literally. Get your tracks up there and join the party.

• BEST FEATURE: Every band you can think of. And more. Much more.
• WORST FEATURE: If you don’t at least have an open mind about listening to dudes playing theremins in their basements, you may as well not bother.
• IDEAL FOR: People so indie that their favourite bands only play clubs in New Crobuzon.

2. GROOVESHARK

I’m new to Grooveshark and have yet to plumb its depths, but let me tell you — this thing packs a punch. Once you get past an initially off-putting interface — it’s iTunes, but yellow — you’ll find yourself in a deep delicious ocean of sound.

One thing I like about Grooveshark? Make that a few things: No signups or registrations to deal with. No limited number of track skips. No mid-song buffering. Freedom of interaction is a big positive: You can skip tracks forward and back, scan back and forth in a song if you want to hear a certain refrain again (just as you could on your own mp3 player) and treat the place like a big musical sandbox.

I’m not sure what Grooveshark’s subscription-based VIP service entails. How can you get better than Grooveshark’s free service? At this rate, I’m figuring it involves swimming in a pool of Cristal and then a trip to the mile-high club aboard a private space shuttle made of diamonds.

To save favourites, save tracklists and access the custom radio stations, you’ll have to register. This is entirely optional, and you can get to the music without it. Playlist creation is a little finicky at first — it’s easy to delete or scramble a listing by accident — but it’s also very powerful, with the ability, much like iTunes, to select multiple tracks in the conventional way, with a shift-click. I didn’t expect such a high level of interaction and navigability from a Flash interface, and I must say I’m impressed.

Grooveshark is a new discovery for me, but I anticipate going back to it very soon. Actually, I’m already there. And how sweet it is.

• BEST FEATURE: Depth, selection, interactivity, speed, etc.
• WORST FEATURE: Design cribs from iTunes, and iTunes isn’t that great to begin with.
• IDEAL FOR: People with functioning ears.

3. SLACKER RADIO

Oookay. Slacker. Slacker doesn’t let you navigate inside of a song. It gives you a limited number of song skips. It requires registration that expires after thirty days, and there are loud and obnoxious pre-recorded DJs in between songs. It requires you to disable any script-blocking software just so their interface will work and the songs will load.

Yeah.

Okay, for the two of you still reading this section… I hope you like Top 40. Because that’s what you’re gonna get.

Seriously. Unlike the other services mentioned in this article, Slacker is heavily biased towards the mainstream. If you let Slacker do the work for you in constructing a playlist, it’ll load you up with all kinds of major-label crap that you’ve heard hundreds of times before on the radio, and probably didn’t enjoy much then, either. Their ‘related artists’ system is a bit of a joke in this regard. In Slacker’s nightmarish, dystopian world, all roads lead to Godsmack. Even roads that started at ambient electronic. Internet research tells me that Slacker is owned and programmed by former satellite radio operators. In terms of musical selection, this may be its chief problem. They should rename themselves ‘I Can’t Believe It’s Not Clear Channel’.

There is an upside. Potentially a fantastic upside. If you have the time and patience to program your own playlists (a bit of a daunting affair, full of micromanagement) you may end up building a real work of art — a playlist crafted by both human and algorithmic hands to feed you new and awesome music every track. Your range of options in this regard is actually quite powerful and easy to administrate, with the ability to choose or ban songs, artists or genres at will.

But Slacker — paradoxically, considering its name — assumes you have the patience and willpower to do this. Not everyone will. Slacker advertises having over 2 million songs at their disposal, but if they’re just going to heap steaming piles of Nickelback upon you anyway, what’s the point?

Slacker’s subscription service apparently features ABC News bites and unlimited song skip ability. Well, sound the vuvuzelas, it’s party time. Or not. In the end, Slacker is for less discerning, more mainstream listeners, and it serves them very well. But I’m not one of them. And those pre-recorded DJs can suck a donkey.

• BEST FEATURE: It’s just like the radio.
• WORST FEATURE: It’s just like the radio.
• IDEAL FOR: People whose radios have just broken and it’s too late at night to hit up Wal-Mart in their H2s while chugging Smirnoff Ice.

4. PANDORA

Most Internet music goons will tell you that Pandora is the greatest overall choice for a personalized ‘Net radio stream with depth and breadth. I hear raves from friends, from blogs, from a lot of corners. Yet I’m unable to decide for myself, because of the blurb that glares at me with cold legal contempt every time I visit the site:

“We are deeply, deeply sorry to say that due to licensing constraints, we can no longer allow access to Pandora for listeners located outside of the U.S. We will continue to work diligently to realize the vision of a truly global Pandora, but for the time being we are required to restrict its use. We are very sad to have to do this, but there is no other alternative. “

• BEST FEATURE: They are deeply, deeply sorry. And sad.
• WORST FEATURE: Due to licensing constraints, they can no longer allow access to Pandora for listeners located outside of the U.S.
• IDEAL FOR: Presumably, people inside of the U.S. But I can’t be sure.

Well, that’s a fine to-hell-with-you. But, ‘no alternatives’? I don’t think so. For instance, I think I hear Grooveshark singing to me in soft, ethereal tones. Time to go listen closer.