Ok, it's no secret that most radio stations are kind of disappointing, especially commercial ones. If you live in an urban area, you might have an awesome local radio station that actually plays good music. You should listen! However, alas, most of the good music might be on 10PM - 2AM on Thursday nights. Or maybe you live some place with Clear Channel, Sony and nobody else? How do you find out about music?
Pandora - for Americans
There's a couple of very interesting online services to aid you in this task, with sort of opposite philosophies. If you live in the US, you can try out something called Pandora. (Outside, the US, scroll down) Alas, it doesn't work outside of the US, but if you can get it, it's actually pretty cool. It's got a very top-down approach. You tell it a song that you like and it guesses what songs you might like based on that one song. You can refine the results by telling it when it's correct or wrong. It's an interesting way to find out about music within (or near) a genre that you like.
How it works is that expert musicologists listen to stuff and classify it. This piece of music is electronic, is 130 bmp, has glitch elements, has IDM influences, uses minor key harmonies, blah, blah, blah. It can alternately make you feel smart when you understand what they're talking about, or it can make you think they're smarter than you. They don't tell you everything about a track, because that would be giving away secrets! But it's not secret that part of what I like about this is that it provides jobs to people with graduate degrees in music. We need the work!
So, you say you like Tag by Agf and it guesses you might also like a few tracks by Boards of Canada. Cool! But, part of the shortcomings of this is that you can't give it more exact feedback. I had a Riot Grrl station set up, which meant I was pretty much only interested in female vocalists, aside from Huggy Bear and the few other Riot Grrl groups with male singers. It just did not get it. And I certainly couldn't tell it that I didn't want to hear sexist lyrics. I could only give it a lot of thumbs down and hoped it would guess that's what they all had in common.
Nevertheless, it's interesting and I would use it again if they offered it in the UK.
Where Pandora is top-down, organized by people who are smarter than you, Last.FM is bottom up, organized automagically using some smart computer algorithms and it's user base. Pandora is like Yahoo, or the Open Directory Project and Last.FM is like Google.
Last.FM is more general and can be used in many different ways. A typical user pattern would be that you go install the spy software called a scrobbler. This software spies on what you're listening to and reports back to last.fm. Ok, it's moderately creepy. However, you can see when it's running and when it's not. When you don't want people to know that you're secretly listening to Esperanto Subgrunda, you can turn it off. Note, also, that Pandora is also tracking what you listen to. If you want to keep your listening habits secret, then you're not going to be able to use any music discovery tool that I know of.
Ok, so you have last.fm installed and you're listening to Madonna, Justin Timberlake and The Coup. Based on that, it's created a sort of radio station of stuff you might like. This doesn't happen because smart people have noted that these artists have a pop sensibility, make heavy use of sampling, have major key and pentatonic harmonies and have a beat you can dance to. No, this happens because a bunch of other users also these same three artists and also like a bunch of other musically-related acts. The correlation happens automatically based on people's listening habits. Nice!
Additionally, you can find your friends on the service (I'm celesteh1). You can go listen to their radio station and see what they like.
Maybe mock them behind their back. And find out they like some cool band that you'd never heard of. Boom, musical discovery based on your friends. It's like the old days of tape trading, but less interactive. In addition to being able to check out your friends, it gives you a list of users who have closely related tastes to yours. You can scope out their stations and also find stuff.
Finally, you can use it like Pandora in that you can just ask for stuff based on an artist or song that you like. It generates a play list and will play it in a web browser or in it's own client. The client doesn't have ads and uses a lot less CPU than a web browser, so it's much less resource stealing to have the last.fm client than it is to have pandora in a browser. But since all the playlists are generated based on what other users have listened to, they can lack subtlety and can be way off for lesser-known acts. I almost never use this feature. However, for example, the similar to Maggi Payne station is really interesting, so it's definitely worth checking out.
Ok, I don't know about you, but I hate making choices. It is possible to use last.fm and pandora at the same time. This is left as an exercise to the reader. Or, if there's interest, I'll do a follow up.
Finally, let's admit it, you think your musical taste is stellar, cutting edge, amazing. You secretly relate to Indy Rock Pete. Ok, maybe that's just me. But you can get some sort of listener creds through last.fm. You can show of how cool you are. (White people like that.) It's appealing, at least at first. And then you miss the new Madonna album or SexyBack and it's all downhill from there. (But seriously, the Confessions on a Dance Floor is awesome. Timberlake? Not so much. But still somehow compelling.) Take it to the bridge.
Ok, what about artists? People are listening to our sol la ti, so we should get some do re mi, right? Indeed. Pandora will only consider CDs with UPC codes. And they don't take everything. "Top down" means curated. But they do pay royalties. Anyway, you can be on both. If you want to be on Pandora, mail them a CD. The pay according to the Digital Millenium Copyright Act.
Last.fm keeps track of everything that people report to it. If you listen to that mp3 of your best friend's garage band while scrobbling, they know about it. Which means that they know about a lot more stuff than does Pandora. If you have mp3s in circulation or a released CD, they probably already know about you. Go look yourself up on the service. Maybe they already have a bio and a picture for you. If they do, it's because some friend or fan set it up - or because you're already famous. If they don't, you can add that stuff. (and terrible candid shots of your musician friends. ahahahaha!) You can also upload some of your own music.
Last.fm has a plan in place to pay royalties, but have not yet started to do so. However even in this pre-royalty time, it's in your best interest to give them a couple of tracks for the same reason that it's in your best interest to put some tracks up on your website. The point is to get people listening to your music through a sort of word-of-mouth(-like) buzz. People see that a friend or musical neighbor has been listening to you. They get curious. They try to listen also. Make sure there's something there for them.