Is it possible to control what music people listen to? Hard as they try, parents can't seem to do it, so it seems unlikely some abstract conglomerate might succeed.

Partly because it doesn't require the massive amounts of equipment and collaboration needed to make, for example, a film, music has traditionally been seen as a medium of cultural, artistic and political expression, an expression which reflects the lives of musicians and their fans - but not one which would necessarily appeal to conservative mega-companies.

Increasingly though, huge media companies own the music industry (an estimated five trans-national conglomerates dominate the world's music market) and as such monopolise popular music, exert control over what we listen to, and even take control of the music, output and identity of artists signed up with them. Artists in countries right across the globe are signed to the likes of EMI (soon to become part of the AOL/Time Warner merged company) and Sony. Contracts are very tight: the case of George Michael and The Artist Formerly Known As Prince, exemplify the difficulties even hugely popular artists have had with "freedom" and record companies.

The companies don't necessarily have it all their own way. However, as global sales of US-based artists began to drop among the largest record companies, they found a way to capitalise on the taste for local music in many countries - they set up local subsidiaries. Sony, in particular, leads the way with distribution deals among independent labels around the world. As profit-making ventures, companies like Sony and EMI are primarily interested in signing musicians who will make them millions. As a result, far from seeking out exceptionally gifted artists who appeal to a relatively small audience, they prefer bands which might be "the next Spice Girls/Boyzone/U2".

Bands determined to make music irrespective of market demands frequently set up their own labels. An indication of just how strongly these bands reflect the values and tastes of many fans is the success of many, many musicians who have just gone and done it on their own (innumerable hip-hop and dance bands, solo artists like Ani Di Franco, etc).

But up against the endless budgets of the bigger organisations, the smaller independent labels which cater for bands that appeal to niche markets are under pressure. Some independent labels are in fact being bought up by the conglomerates.

So where does this leave both cultural expression and freedom of fans to listen to music of some relevance to their lives? As Robert McChesney, author of Rich Media, Poor Democracy, says: "With growing corporate control comes an implicit political bias in media content." What form does the bias take? "Consumerism, class inequality and individualism tend to be taken as natural . . . whereas political activity, civic values and anti-market activities are marginalised . . . media conglomerates exist simply to make money by selling light escapist entertainment."

Not a pretty picture for a rebellious teen spirit in search of self. However, McChesney also expects "widespread opposition to these trends, calling into question . . . the neo-liberal economic model and the global media system it has helped create".