Thomas Sutcliffe: Computers can't tell me what to like

The technology of personal taste gets more sophisticated by the day. If you use Amazon regularly to buy books, you'll already be familiar with its automated methods of making the virtual shop window respond to your whims - laying out a selection of recommended titles based on your own previous orders and the kind of collective penumbra of taste it suggests. Last week, though, I was introduced to a website with even more precise designs on your purchasing power. Pandora.com offers to create a bespoke radio station for you - drawing on what its designers call the Music Genome Project.

The initial enterprise was both simple and eccentric - like a pub game that got out of hand. The originators of the project set out to identify the elemental genes of popular music by analysing thousands of songs according to various attributes. These might include anything from the "vocal-centric aesthetic" to "major key tonality" or "an upbeat two-step feel" (all features of Led Zeppelin's "In Through the Out Door", as it happens). The genome they ended up with allows the website to predict what kind of music you might like. Give it a sample of your passions and it will stream a selection of genetically related tracks - some familiar and some not. If you don't like a song, you can skip to the next one. If you do like it, you can find out more about it and buy it online.

That's the point, of course. This isn't some kind of selfless, shareware idealism - fuelled by muso passion. It is a clever kind of advertising and the heart of its cleverness is the flattering implication that without your unique personality, the thing wouldn't be possible at all. There are limits to its generosity, though. You can bookmark songs but not replay them when you want. And if you skip too many songs, the screen throws up a message explaining that the site's music licences force it "to limit the number of songs you may skip each hour". The idea wasn't to create a universal jukebox on random select, after all, but to fine-tune the marketing tool of radio airplay - which depends on holding music just out of reach. And, so far, they haven't worked out the licences for British listeners. You can try out the service - but if you can't come up with a plausible zip code (aka delivery address), you'll eventually be frozen out.

On the face of it, Pandora.com and all the other automated suggestion services are an empowerment of the consumer over big business - and if not an empowerment, at least an equalisation. You get to dictate what is put before you, they get more bang for their marketing buck - and everybody wins. In practice, though, I can't help wondering about the inclusion of a mainframe computer into the odd-and-unpredictable business of enlarging your own cultural experience. For one thing, choice and liberty are vastly overrated as methods of developing aesthetic taste. The absence of choice can be just as important - a trivial example being the increasingly endangered experience of learning to love the track on the album that comes between the two you initially much preferred but which have now lost their savour. What price patience or endurance of the unfamiliar in a world that allows you to fast forward as soon as you find something challenging or unexpected.

For another thing, we all know that a sharply defined sense of personal taste is only a whisker away from a kind of bigotry. "I don't like that kind of thing" delivers its verdict before any real evidence has been laid before the court. In fact, whenever I encounter these algorithmic devices for narrowing the gap between my taste and my purchases, I get an image in my head of a memorable scene from Fantastic Voyage, that science fiction classic in which a group of doctors are miniaturised and injected into the body of their patient. At one point, Raquel Welch is attacked by antibodies, which swarm at her from every direction and clamp to her body. As they tighten their grip, the crew have to desperately prise them off her body to prevent her being asphyxiated.

And that seems to me not a bad image of the way that websites tailored to your taste clamp a kind of armour of the inoffensive around you. You could easily end up stifled by your own likes - with not a gap left for fresh air to get through. Personally, I prefer to leave room for happy accident and the mind-changing surprise; for those things that chip away at my established taste rather than simply reinforce it. Such customisable and responsive sites give you the illusion that you can use the computer to express yourself. But how can you be sure that the computer doesn't end up expressing you instead?