WIRED:THE INTERNET has frequently been cited as the most cunning tool of jihadists and radicals of all stripes. We are told how that most medieval of organisations, al-Qaeda, has used the internet for recruitment and morale, spreading videos of its propaganda on YouTube and plotting its next attack on discussion groups buried in the hidden corners of the global communications infrastructure, writes Danny O'Brien

Closer to home, commentators fret about the rise of hateful discussions on comment boards, and worry if it will spill over into real-world violence.

Is it true? Last week, I visited New York and spoke to individuals fighting terrorism. They agree that their targets - radical extremists, white supremacists and other advocates of violence - use the internet. They also agree that the best response is not to restrict the use of the internet, but to use it to fight back.

At the time of the September 11th, 2001, attacks, the internet and radical Islam had barely been introduced. In places such as Pakistan, the web was viewed as another of the West's lurid, freewheeling blasphemies.

But for Evan Kohlmann, a private consultant who monitors al-Qaeda and other terrorist groups online, the globalisation of al-Qaeda's war coincided too perfectly with the globalisation of the internet for them not to use it and be moulded by it.

According to Kohlmann, in the early days of al-Qaeda's web presence, the single "official" website of the jihadists came and went, as it was identified and shut down by western law enforcement - or, more often, by shocked hosting providers, who had no idea what they were offering to the rest of the world.

But within a few years, radical Islam online had not one central authority but a dozen or so major forums among many thousands of wannabe terrorist sites. Out of those, a few - some of which, Kohlmann says, are London-based - were allegedly picked by those on the ground in al-Qaeda to be the recipients of "real" news: videos, diatribes and invitations to fight the jihad from apparently genuine terrorist leaders.

Direct links are hard to prove in any modern terrorist network. But there does not have to be a direct link to worry modern anti-terrorist organisations. Just as the internet has been a boon to ground-up, word-of-mouth campaigns for politicians, pop groups and personalities, so it has with extremists.

Al-Qaeda does not need to have high-ranking leaders logging on to the internet for its sympathisers to build their own self-supporting infrastructure. Kohlmann cites the huge number of video clips of attacks on US troops in Iraq, set to music and intercut with imagery of Islamic fundamentalist fervour and Osama bin Laden speeches.

The folk songs of al-Qaeda - tracks with titles like I am a Terrorist - are shared, remixed and dubbed as quickly as filesharing networks spread popular songs.

Estranged teenagers in Baghdad, Paris and London pool their anger and exchange diatribes.

And it's not just Islamic terrorism. Mark Potok of the Southern Poverty Law Centre says the internet has enabled hate speech to increase in the US. The centre recently reported a worrying rise in white supremacist activity after the election of Barack Obama, and now documents online domestic extremism on its website.

But does that mean the free speech that the internet enables is working against the best interests of a free society? Is the solution to this explosion of extremism to put the brakes on the internet's freewheeling infrastructure of open expression? Some western countries have already proposed - or implemented - filters and blocks for child pornography and other prohibited content. Would it make sense to block and filter extremes of political discussion when it verges on "glorification" and recruitment for violent causes?

Zahid Jamil, a lawyer working in Pakistan, says the answer to these messages is not more filters or laws against internet speech, but more speech.

He calls for an "army of bloggers" to challenge terrorist support on its own ground: providing the stories and counter-arguments that other local media cannot or will not supply.

Potok says the best stance against extremist speech is not "quarantine" behind blocks and filters but "inoculating" those it preys upon by showing them alternatives.

The Southern Poverty Law Centre's own blog is unmoderated, Potok says, because of the organisation's belief that the supremacists and other far-right groups it deals with are better addressed in the open.

If the internet is a tool for jihadists, it is a tool they can only use by swallowing a contradiction: that it is the western tools of free speech that enable them to convey their opinions.

It's a contradiction that many intolerant groups have exploited in the past, but it still serves to weaken their message. If we were to filter or block, say, those who fight and monitor these groups at close quarters, we would be undermined by our own hypocritical behaviour.

Better to leave the internet as it is: as a tool for everyone, and as an everpresent counter-example for those who want to deny its power.