One of the things that’s fascinating about the UK Top 40 is that a device designed to be a pure expression of popularity also works as a reflection of so many other things. People buy songs: if enough people buy a song it gets into the charts, or to #1. Simple! But so simple that it neglects one very important element: why somebody is buying a song.

There’s a baseline assumption that people are buying a song to listen to it because they like it. But of course that’s not the only reason: often people buy songs because the song is part of a wider experience. A world cup, a summer holiday, a movie, a TV show, a human tragedy. This isn’t “hijacking” or manipulating the charts: the pitiless charts, after all, don’t differentiate between purchases out of loyalty, love, or grief. A song bought as a souvenir has still been bought.

This is important for understanding why the X-Factor winner gets to #1 every year. People who dislike the X-Factor often criticise it for reducing music to a soap opera, but this misses the point: it’s rather like people who slate wrestling for not being a proper sport. The X-Factor is a narrative which happens to involve music. It’s an interactive narrative, and it’s a multimedia narrative, with a central thread (the weekend shows) crossing over into magazines, newspapers, YouTube, Twitter backchannels, et al.

Millions of people follow and participate in this story – pick sides, vote, shout at Simon Cowell from their armchairs, wonder what it means that Lloyd gets through for another week and Miss Frank don’t, and so on. The music is a necessary part of the story but it isn’t the story itself: light entertainment is simply bigger than pop, always has been. 19 million people watched the X-Factor final, a figure four times higher than the total sales of this country’s highest-selling single EVER. They’ve followed the X-Factor not because of the amazing pop it might or might not produce, but on its own terms as narrative and spectacle.

So where does the winner’s single fit in? In the Guardian, Peter Robinson called it a “lap of honour”, and this is roughly the truth: it’s a way of celebrating the achievement of winning the show (itself as tough and pressurised a gig as reality TV has to offer) not a look forward to the winner’s career (or lack of it).

But the charts being the charts, people still have to buy the single in sufficient numbers to get it to No.1. One of the odd things about the Rage Against The Machine anti-X-Factor campaign is its apparent belief that Simon Cowell has mind control powers and that the people buying Joe McElderry’s single are somehow under his command. The focus on Cowell rather than on the Joe buyers is a sensible one – best not to dwell on how the machine you’re raging against is actually your auntie or your kid sister. But honestly the Joe fans aren’t buying a song because Simon tells them to, any more than Russell T Davies is forcing me to buy a Doctor Who DVD set. They’re buying a song either because they like it, or because it’s a souvenir of an experience they enjoyed, or both. They’re playing one last part in the series’ shared narrative.

And why are RATM buyers buying that? Much the same reason – they have a narrative too. It’s a cruder one – stop the X-Factor winner from getting to number one and piss off Simon Cowell. It’s a shorter one – built up over the space of a week or two. But there’s a lot of inarticulate power around it: for many buyers it taps into a more general frustration with pop and music and reality TV and the charts and a sense that “real music” doesn’t get its just reward any more. And to some extent “Killing In The Name” has always been “Frigging In The Rigging” with dreads and a conscience, so there’s an understandable element of adolescent glee around the whole thing.

It might work (though I said that last year too): there have been a lot of these kind of gesture aesthetics campaigns in the last couple of years and sooner or later one of them will come off. The charts are a perfect ground for it: because they’re so digitally driven now there’s no physical cost in buying several copies of a single, no pile of “Killing In The Name” cluttering up your home when you already own it. Buying RATM is basically casting a vote in a big poll, except you have to pay to vote. Much like an X-Factor phone-in, in fact.

So the whole thing comes down to a clash of stories, or rather a clash of people paying to be part of a story. The big difference is that what’s at stake – “getting to #1” – doesn’t really matter in the Joe McElderry narrative (where the single is a reminder of a story that’s already had its happy ending) but is the entire point of the Rage one, which means the Rage story has force and momentum on its side.

Plenty of people have pointed out that these are good times indeed for Sony, who make money off both tracks. But it’s also a fascinating case study for marketers, because it pits two of the big “social media marketing” ideas of the late 00s up against one another. On the one hand the crafted, immersive, interactive experience – on the other the power of the flashmob and the viral. Who’s gonna win?