After Bob Naiman and a bunch of fellow activists drew straws last year to throw a pie in the face of the managing director of the International Monetary Fund, they hit a snag.

Michel Camdessus, then the head of the IMF, had come to give a speech in Thailand. The local stores, however, did not stock the kinds of custard tarts or cream pies his critics were looking for. In the end, they had to make do with a sponge cake from a Bangkok outlet of Seven-11.

"I always worried that people would find out we bought the offending pie from a Seven-11," recalls Naiman in a shirt and tie at a Washington think-tank, styling himself these days as a campaigning economist. "Just think, anti-globalisation campaigners stocking up at a Seven-11."

Anti-globalisation has piggy-backed on globalisation. The resources, infrastructure and technology of a globalising world have enabled - or, in Mr Naiman's case, armed - the anti-globalisation movement.

On the streets of Gothenburg in June, the demonstrators orchestrated their protests by sending text messages over their mobile phones. When the organisers of the World Social Forum decided to host a summit to counter the annual Davos get-together of industry leaders, they met in Porto Allegre, Brazil. Cheap international airfares made it possible for activists to get there.

But the biggest single resource for the counter-capitalist movement has been the internet.

"Some of these issues and movements have been around for years. So what is new now? It is the technology." says Moises Naim, the editor of Foreign Policy, who says he has turned the magazine into what is effectively the journal of globalisation studies. "Just imagine how much the Christians could have achieved by the third century armed with the internet. . .If each activist has at least two feelings in common, it is probably these: We know more. And we can do something about it. The internet has been largely responsible for both."

It enables the Mobilisation for Global Justice to reach not just hundreds of thousands of people, not only to mobilise protesters but also find housing and arrange transport for those coming to demonstrate in Washington at the end of the month.

Not all the people aligned to activist groups are online. Not everybody who gets sent a campaigning e-mail reads it. But the pace of growth of counter-capitalism would not have been possible without the internet.

The web is also the source of the facts and figures and opinions which informs activist thinking. In a converted garage behind a row of terraced houses which serves as the headquarters for Corporate Watch UK, Rebecca is part of the online information movement. The Corporate Watch mission, she says, is 'to expose corporate power.' How does she do that? "Well, all you need is the internet and the Google search engine," she says. And, for other activists, news and analysis from the likes of Indymedia.org and Znet.

A couple of years ago, a steelworker was surfing the internet to see what he could find out about the Maxxam Corporation. He and his co-workers were campaigning against Kaiser Aluminum in Spokane, Washington. On the web, he found a bunch of environmentalists were fighting Pacific Lumber in northern California. Both businesses were owned by Maxxam Corporation, a company run by Charles Hurwitz. So, he suggested a get-together of the two groups - the workers in their overalls and boots and the environmentalists in their dungarees and Birkenstocks. The idle surfing gave birth to the Turtles and Teamsters combination, the blue-green coalition which was such a feature of the Seattle protests. More enduringly, it spawned the Alliance for Sustainable Jobs and the Environment, which today has 53 member organisations and lobbies members of US Congress not to give the US president unilateral authority to negotiate trade agreements and rewrite the rules on global trade.

To those very few activists who have both a sense of humour and a grip on technology, the internet has also been a means of subversion.

The Yes Men are arguably to online pranksterism what the Oz editors were to inky newsletter activism a generation ago. They are not a formal group, but a gang who make mischief impersonating people.

Having commandeered the gatt.org web address and established a hoax site, last year, The Yes Men fielded a request for Mike Moore, head of the World Trade Organisation, to come and speak at a Salzburg gathering of lawyers. In an e-mail exchange, 'Mike Moore' declined but sent an invented deputy, Andreas Birchlbauer. Dr Birchlbauer attended the conference and made a bewildering speech, noting that the Italians have less of a work ethic than the Dutch, the Americans would be better off selling their votes to the highest bidder and that the WTO's main aim was to create a one-world culture. The internet had got Dr Birchlbauer through the door. (Appropriately enough, a member of the Yes Men could not be met in person, but a friend confirmed the story.)

In the closing years of the 1990s, dotcom entrepreneurs and online investors trumpeted the fortunes they were set to make on the internet. The online world would revolutionise communication. It would build new communities. It would tear down the walls which restricted distribution and create an information free-for-all. And it has done all those things, except make those fortunes. Instead, some of the the biggest winners of the internet revolution have not been people fighting for profit, but against it.

Part Four: Inside the Black Bloc

Contact James Harding at james.harding@ft.com