You have to ask what we come to these film festivals for,' asked a producer, his mouth full of pintxos as the sun set over La Concha in San Sebastian a couple of weeks ago.

Leaving aside the obvious merits of location, the grand 'What are we for'' questions are sounded more frequently at industry gatherings. In the last month, you may easily have had similar conversations about release windows, markets, sales agents, single-territory distributors, independent theatres...

It's healthy that in a period of radical change, people do not have their heads in the sand. But navel-gazing is little better. 'What are we for'' is surely a question that requires a response.

And when we look at all of the above, the answers are broadly similar.

So far as any part of the business advances the ability to reach increasingly demanding audiences as efficiently as possible, it can survive. If not, then the future looks considerably less certain.

Film festivals have an advantage in that they generate their own audiences. In many ways, the best festivals are what the online world calls social networks. Some bring together business interests in one place through markets; some connect cities with cinematic culture; some are glorified fancy-dress parties for the genre-obsessed.

But the festival does something else - something that lies at the heart of film's place in the world. It endeavors to surprise and challenge. Laying out the tapas and wheeling on the odd celebrity may draw a crowd, but it is the ability to introduce those people to new ideas that is the divide between success and failure. You don't go to a festival because you know what you want, you go to find out something new.

Looking back at 2008, who knew war films could go through the kind of animated reinvention Ari Folman offered with Waltz With Bashir or that a documentary-style study of a school could illuminate society and humanity in the way Laurent Cantet managed with The Class' The challenge of the new, and the arguments that follow, are the lifeblood of cinema. Yet it is the crucial quality of serendipity that is most threatened today - ironically by the illusion of choice that today's media throws up.

What the explosion in the number of television channels has done is reduce our exposure to the new. How many of today's arthouse fans discovered their passion in what were once peak-time shows in a television environment of two or three channels' Now there are far more opportunities to see a given film on television through cable or satellite, but the spread of channels has both reduced the potential to find and nurture new audiences and undermined the potential revenue from pre-sales (see feature, p16).

There's no putting the lid on Pandora's box. We live in a multi-channel universe where people can find what they think they want, but without the breadth of view to discover where film might take them.

But if the future of film depends on (a) audiences and (b) surprise, then there must be answers.

The challenge is first to create and nurture audience networks. Then it is to interact with that customer base both in offering products they want and in gaining the trust that means offering product it doesn't yet know.

That approach is obviously open to festivals but it is surely also of interest to a new breed of sales agents, distributors or indeed theatres. The relationship between producer and audience remains ludicrously wide but we have the networking tools available to introduce at least some demand-led services - cinema on demand, virtual festivals, specialist clubs and so on. Anyone can stand up and say the sky is falling in for the independent industry but it's surely time to shift the attention to the future.

Next week, UK industry leaders meet in Screen International's annual film-finance summit (see It is always a chance to check the health of a major international industry. Perhaps this is a good time to judge the business not by revenues or production figures, but by the serendipity test.