Acting on his concern, Schwartz and 10 other web developers built www.haitianquake.com, an online lost-and-found site to help Haitians in and out of the country to locate missing relatives.

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The database, which anyone can update, was online less than 24 hours after the earthquake struck, with more than 6,000 entries due to a built-in "scraper'' that gathered data from emergency relief organisations working at the site of the earthquake in the Haitian capital of Port-au-Prince.

Agencies, including the International Committee of the Red Cross and the US federal emergency management agency [Fema], put the systems to use and two days later, Google, the US search engine giant, created PersonFinder, which consolidated all the information from various person-finding sites.

Christopher Csikszentmihalyi, the director of media at the Massachusetts Institute of Technology, said PersonFinder, which can be embedded in any website and thus far has more than 32,000 records, "greatly increases the chances that Haitians in Haiti and abroad will be able to find each other".

Dispatching rescuers

Another volunteer project forged in the earthquake's aftermath was a mobile phone text-messaging system that helps relief groups dispatch rescuers, food and water.

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Patrick Meier, the director of Crisis Mapping and Strategic Partnerships at Ushahidi, an online crisis-reporting platform, told Al Jazeera such tools allow near real-time disaster response.

"One of the most recent developments in that effort has been the free text messages [they are usually in Creole but in 10 minutes we get them translated into English] ... if anyone inside Haiti texts 4636, we get that information in near real time and can [then] map it [and get the information to organisations that need it]," he said.

"We have had a number of success stories. One of the very first was a report that went up through Ushahidi about an orphanage that was desperately running out of water ... soon after we had someone report they had dispatched 20 litres of water to the orphanage."

In another collaborative effort, volunteers from online OpenStreetMap "crisis mapping'' project provide up-to-the-minute data, such as the location of new field hospitals and collapsed bridges.

The information, updated by everything from feeds on the popular microblogging site, Twitter, to witness reports, has helped aid workers get food, water and medicine to where it is needed most.

The number of people killed in last week's earthquake had risen to 75,000, with another 250,000 injured and one million left homeless.

The UN food agency has distributed rations for nearly 200,000 people.