The chance to construct a new society is the stuff of dreamers and proselytisers. It is centuries since every readily habitable corner of the earth was populated, and constructing ideal communities has been limited to model towns and Utopian settlements. Until, that is, 30 years ago when Tim Berners-Lee's world wide web conjured up a truly virgin territory. A place of almost unimaginable opportunity, it used to seem beyond doubt the web would be ruled by a spirit of shared community, a source of individual empowerment against corporate and political might. But it has become increasingly apparent that this web is under threat, and the question of how it should be governed, in whose interests, and for what purposes has become a debate of overwhelming significance. That is why this week the Guardian has been debating how best to preserve its original spirit against both corporations seeking to corral users into marketable segments, and state power in pursuit of control and censorship.

The internet has been used as a force both for creation and destruction. The appetite for freedom has laid waste to the traditional business models of music and publishing, film and newspapers, but the same accessibility and intercommunication has facilitated a democratic cultural explosion and created unparalleled possibilities for spreading information. It also offers an unprecedented opportunity for surveillance; it exposes its users' habits and preferences, the very stuff of privacy, to commercial harvesting. It mobilises communities and creates crowds that can threaten dictators – but it also leaves democracies vulnerable to cyber-attack. It could be the new frontier in a cold war, or a space that breaks down barriers – or both of those things at once.

What is clear from the debate is that the direction of travel is towards new kinds of ownership. There is the complex issue of quasi-control by states concerned with their own security, where the capacity to track terrorists or paedophiles has to be balanced with the use of the same potential against Syrian protesters or Bahraini dissidents. And there are the walled gardens created by Facebook and Apple, where users enjoy a degree of protection from the internet badlands of malware and spam, but from which Google's indexing algorithms are also excluded. Yet Google's own version of freedom is only partial. The price of enjoying it is the delivery of your behavioural choices (and sometimes much more personal data) to their advertisers. It prefers to keep a toehold in dictatorships at the cost of compromising its own commitment to making the world's information universally available. And finally, there is the demise of the user-programmable PC which is being replaced by the closed system of the smartphone and the iPad, threatening the capacity to stand on the shoulders of past giants that has made the internet so creative.

The future will not be like the past. The question is how to preserve the public commons that is the web's greatest asset, in an environment where few old rules apply. No legal system has yet been devised to contain the monopolistic tendencies of things like Google or Facebook. In this territory without limits, legal concepts like copyright have little traction. Only the new law of intellectual property offers a way of protecting commercial frontiers.

That might offer an indication of where the battle really has to be fought. Appropriately enough for the defence of this precious utopia, for now at least this must be a battle between philosophies. To protect the web's founding principle is a matter of what Tim Berners-Lee would call citizen vigilance, of restraining by openness itself the continual pressure for a closed-down, privately owned cyberspace that is the inevitable product of those internet Cecil Rhodes who would like to fence in the riches of the virtual world. It must be a web not for the consumer, but for the citizen.