Wired on Friday: With over 3,000 songs to choose from, SongFight.org is quite the online musical treasure trove.

Or it is, if your tastes are for the amateur, the unsigned band, the one-hit experiment, and the occasional total stinker. This is not iTunes. There are no big names here, and no fees: these songs are free to download, provided by artists who don't expect to receive a penny for them.

SongFight's contributors aren't doing it for money or fame. They're doing it for the thrill of the fight - and that carries its own implications about how and why people create, how they might improve their creations, and the murky future of the music business.

Here's how it works. Every week the site's maintainers, the anonymous Fightmasters, put an invented song title onto the front page of the site. Contributors have a week to create a song that fits the title, which they rapidly write, record, digitize and upload to the website for anyone to hear. The Fightmaster's titular choices range from open-ended inspirations like Run Free or Secrets to the truly challenging, like I Don't Like Eggplant or Don't Forget to Come to My House on Wednesday. You can't bend an existing song to fit the title. Covers are definitely verboten. And whoever gets the most votes from those who download and listen to the songs wins the 'Songfight'.

But the SongFight community doesn't just come to listen and vote. On the site's online discussion forums, they talk. Every week the reviews come thick and fast. The SongFight audience is rarely unanimous on the best (although there's always consensus on who is the worst). And with much of the community recording its own 'songfights', much criticism comes with friendly, experienced advice, some of it highly technical, on what works. And if you lose the fight, don't worry - there's always another 'songfight' along in a moment.

Think of it as 52 Eurovisions, with each learning from the last, or an endless musical academy.

As you might imagine, much of the music is so-so. Some of it is terrible, in a college room-mate with a guitar kind of way. But, to be honest, very little of it is boring, and none of it is pressed out of a studio boy band mould. There are sounds here that no A&R man would ever hear, no matter how many small town gigs he visited.

SongFight has even witnessed the birth of a genre: Nerdcore, a kind of hip-hop focused on the geek-friendly themes of unpopularity and under-achievement, pioneered by community member MC Frontalot. Nerdcore is making no-one rich (yet), but it makes many unpopular and underachieving geeks (including your columnist) very happy. And you'll never see the winner of I Don't Like Eggplant fight (with vocals by a precocious seven-year old) in the shops, but it's a fun track, and I'm sure it graces the MP3 players of many a SongFight fan. SongFight brings fame, but not fortune.

But still the songs come, dozens a week. With the open audiences that the net provides, the search for status among peers or the plain desire to get something done can be as much of a motivator for making music as the promise of a record deal.

As one of the Fightmasters - still determinedly anonymous - says: "There is an immense satisfaction to be gained from the act of creation. Sometimes these people have what you might call a craving, or an itch that they just don't know how to begin scratching."

That sounds suspiciously like one of the great tenets of open source, coined by Eric Raymond, in his Cathedral and the Bazaar: "Every good work of software starts by scratching a developer's personal itch".

Does that mean the great behemoths of music will soon be threatened by a horde of scrappy little open source musicians? Even the Fightmaster feels that's unlikely. "Online music is still small potatoes. The major labels flood the world with content and promotion, and the problem with that is only in where they choose to focus their efforts."

Online music may be tiny compared to the commercial world of music, but there's no shortage of material for the determined browser. Sites like iuma.com, archive.org, somesongs.org, and ukbassline.co.uk host hundreds of thousands of songs that artists have made available for download. Certainly more than you could possibly listen to in a lifetime.

Music labels often claim that without financial incentive, music-making would die, like an underfunded branch of heavy industry. SongFight and its sister sites show that music is rather more similar to poetry. We know that nobody pays poets much any more, but there's no world shortage of poems.

Of course, that surfeit of free music presents its own challenge. With money no limit to your collection, there is still a need for some entity to provide a filter.

The net is slowly beginning to figure out how to perform this function. Some sites like Iuma use the number of downloads to create a top 40 chart system, like the traditional measure of success in the world of labels. Other sites like SongFight use user ratings to help the cream rise to the top.

In these small musical communities the feedback loop is tight between the artists and their listeners. In SongFight, a person will hear a great deal about his song, and can come back in a week and try again.

But is this any different to the strictures and discipline of the struggling, unsigned band, making the rounds of the pubs and dives? Does it improve the music more than traditional venues for amateur music? Despite the name, the SongFight environment seems more tolerant of peculiarity than a room full of strangers. "Long-term involvement refines a participant's ability to execute their vision," says the Fightmaster, although he admits: "Some people have what I'd consider a very strange idea of what's good". But that's what online life is all about, whether it's blogs, or code, or music; variety over homogeneity, at the cost of broader celebrity.