Cinema on demand is one of those long-touted ideas that's become a cliche before the fact.

The idea of customers taking control of the programme in their local theatres is among the most compelling dreams of digital cinema (though evidently not quite compelling enough to break through the impasse in adoption in much of the world). Still, we're about to see a bona fide example of a trend that I guess will be trying its best to avoid the acronym, COD.

Brazil's pioneering Rain Networks group has officially launched its take on the idea - MovieMobz - in Sao Paulo. Customers sign up online to the initiative and pick the films they want to be screened from a menu of available movies.

Exhibitors seem to like the idea, happily accepting the opportunity for a full house on those dead nights with the customers making all the effort. It's not difficult to see cinema on demand spreading widely. It looks like a marriage of convenience between technology and demand.

Founder Fabio Lima sees it as the response to 'long tail' theory. In reality, it's the very thick end of the tail.

Cinema on demand remains restricted by both days of the week and screen space. The most obvious short-term economic benefit for exhibitors is filling the gaps in the schedule. But the limitations of the system will become obvious if scaled up to the wider world. What happens when a mobilised audience wants to see A Bout De Souffle on a Saturday night when the bread-and-butter studio is demanding four screens of Spider-Man 10'

Nonetheless the idea of audience-led cinema programming throws up some intriguing - and potentially disruptive - notions. Just suppose a German audience mobilises to demand an Austrian film that does not have a distributor. Film sales on demand is an intriguing idea, even if it throws into question the role of sales agents.

Such ambitions may prove fanciful. A form of cinema on demand is likely to win widespread adoption around the world but it will be much more mundane. It will probably be a bit of social networking to create engaged and demanding audiences; a little listening to schedule advice from the customers; and with any luck attracting nice niche audiences to nasty holes in the schedule.

More interesting is what on-demand cinema says about the reality of customer taste. Much has been made of a supposed drop in interest in independent film in the US, and particularly the death of the theatrical documentary. 'One thing I learned is that topicality doesn't sell a ticket,' ThinkFilm president Mark Urman told The New York Times this week. He's articulating the seemingly self-evident view that, fuelled by the success of Michael Moore and Morgan Spurlock, the industry went on a binge, only to find the cinema doc was a passing fancy. But it's not the documentary, or other specialist fare, that is dying but their ability to generate money under the current system of distribution. Arthouse or documentary audiences are dissipated geographically - bring them together effectively and you have a business plan.

That, of course, is the promise of the internet but it won't be easy. Leading analyst Lehmans this week produced a gloomy forecast for the studios. Digital distribution will disrupt profits on high-yield physical products such as DVD, it says, but won't provide a short-term revenue replacement. Efficient digital distribution will not be a licence to print money. Demand-led business is clearly going to be subject to the same long-odds for success as the current analogue world - at least in the short term.

Niche distribution and customer-led approaches are still far from simple and the ratio of hits to flops will soon settle into a familiar pattern. But if one let the likelihood of commercial success be the prime motivation, you'd never get out of bed. If you're looking for an optimistic sign, it's simple: this year's Stars of Tomorrow (see ^p12) are no less talented or scarcer than at any other time. And what customers demand most of all, is to be entertained.

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