Hardened chart nerds – and as you might imagine the FT staff includes a few of them – are in a mighty froth over this week’s Top 40 revolution, with download-only tracks (i.e. with no physical presence in, or planned to be in, the shops) eligible for the first time. In practise this probably means that the middle bits of the Top 40 will be clogged up with old pop – supposedly the Proclaimers and Snow Patrol are set to benefit most from the new format come Sunday.

The BBC’s coverage of the change strikes a familiar note towards the end – ‘it is hoped’, apparently, that the new rules will see a return to singles rising slowly up the charts.

The desirability of this has been a party line ever since the singles chart (or its radio and TV vehicles) began to decline in influence. Why is it a good thing? The general explanation is that it makes the chart more exciting – but in America singles rise and fall on the Hot 100 all the time, thanks to the ebb and flow of airplay, and no Americans seem to remotely care about their chart. Certainly nobody would call the Billboard charts, with singles hanging around the Top 20 for half-year stretches, ‘exciting’.

The actual reason is simply that pundits have latched onto something that used to happen when the singles chart was more popular, and made the assumption that the decline of that thing and the decline in popularity of the chart must be linked. This is poor reasoning, since the two declines have quite different roots.

The decline in interest in the singles chart is, I think, linked to two other factors: the opening of the “official” charts up to competition (lessening their authority and reach), and a decline in singles buying which has been a long-term trend, only recently reversed by downloads. The reason downloads have reversed this trend – and the reason the trend had taken hold in the first place – is that physical singles are pricey and inconvenient relative to albums, and downloads aren’t. Not because downloads have a mystical ability to climb the charts in exciting ways.

The decline of “climbers” in the charts, meanwhile, is simply down to improvements in distribution and marketing. Release dates are more widely publicised, fans more easily mobilised, and records reach shops more consistently than they did twenty years ago. There have always been records that charted high and didn’t climb: they were the ones made by acts with highly established fan networks who made it their business to know – and let one another know – when a new record by the Jam or U2 was out. Once the record labels worked out how to get this information out more efficiently the days of the climber were numbered.

So there’s nothing inherently ‘healthy’ about records climbing the charts. Which is just as well, as the new rule changes will make things less stable, not more. Online promotion means that word of a new track can spread immediately to interested purchasers, who will be one click away from a sale. Meanwhile reaction to an external stimulus – an advert or the use of a tune in a TV programme – will also be near-instant. The proportion of records charting and vanishing within a week or two will surely rise.

And indeed the spin on the new rules is shifting as the first midweeks come in. Here’s Mark Goodier, “Voice of the Charts”, talking them up in the Sun. The idea now is that these new-look charts will be a triumph for populist democracy, with the tantalising prospect of an all-Beatles chart held out for our bedroolment, and a boo hiss to the evil record companies which have been gerrymandering them for so long. It sounds like we’ll get the worst of both worlds – charts which no longer offer a high turnover of new music, but which are crazily unstable at the same time. The researchers behind the charts, like any other researchers, have framed the scope of their survey so that its results can tell a story at any given time: the new rules make that considerably harder.

But at the same time it is quite exciting, in a geeky way. Exciting, but is it pop? Speaking as a marketer, it’s a marvellous development: suddenly a publically accountable metric of effectiveness for licensed advertising, film and TV music is available, and a public data set allowing us to accurately track exactly how consumers respond to music-related events (including deaths, weddings, scandals). I’m rubbing my hands together in anticipation.

As a chart fan and writer, though, I’m a bit worried. Since I started Popular, I’ve come to appreciate even more what a finely calibrated machine the UK Top 40 has been – reflecting almost all major musical trends and fads, but at the same time able to warp and shift to accomodate the impact of other entertainment media: TV stars, film soundtracks, charity records, advert music, all forces buffeting and shaping the ‘ecosystem’ of the charts. The new rules may well make the charts even more sensitive to these ‘external’ events, destroying any sense of coherence, of underlying trends or developments in pop. The record companies Goodier rails against may well have treated the charts as their own narrative to plan and ‘write’, but with everything up for grabs, will they perhaps stop making any sense at all?