Guardian Unlimited reports on the reaction of citizen journalists to the tsunami and relief effort.

Within a few hours of the quake, users were logging on to communal online encyclopedia Wikipedia and compiling a breakdown of what had occurred, including scientific analysis, links to news articles and ways to give aid. Online retailer Amazon organised a huge fundraising effort, with users donating more than $9m (£4.7m) to the American Red Cross in the first week alone. Bloggers signed up to keep information running at the South East Asia Earthquake and Tsunami Blog ( http://tsunamihelp.blogspot.com), created in response to the disaster.

“In only a week this site comes up third on a search for ‘tsunami’ on Google,” says Jarvis. “That demonstrates the power and speed of the mob through its links. People immediately spread the word and gave this new site ‘authority’ as we now measure it online - they gave it links.”

University of Tennessee law professor Glenn Reynolds - whose weblog, www.instapundit.com, is one of the world’s most popular - believes this effect has been seen before on the web. “The blogosphere traditionally rallies in crisis,” he says. “It has its origins in the post-9/11 rallying.”

In many ways he is right. When terrorist attacks left America trembling in 2001, the internet made a breakthrough: thousands of weblogs suddenly turned their attention to New York and Washington. Since then, the focus has been on weblogs as newsmakers. But now, in the wake of the tsunami, weblogs have become a support network, giving weight and context to an existing story.

Howard Rheingold, author of Smart Mobs: the Next Social Revolution (www.smartmobs.com), believes this was partly due to the realisation that existing systems just were not strong enough to cope with a disaster of this scale. “I think this was a wake-up call for grassroots disaster relief,” he says. “The instances that were blogged… will inevitably lead people to come up with better solutions [in the future].”