Just a few hours after Japan was devastated by an earthquake and tsunami early on Friday morning, people mobilized online to help.

Within two hours of the Japanese earthquake, a version of Ushahidi, Web software that helps people share information during a crisis, had been created by Japanese volunteers working with the Fletcher School at Tufts University. Ushahidi consists of a Web server and other software that lets anyone send in information—via a cell phone and the Web—that is then displayed on a map. The site dedicated to Japan, sinsai.info/ushahidi, is being used to pinpoint locations where people may be trapped, dangerous areas that should be avoided, and supplies of food and clean water.

Ushahidi was originally created to coordinate information relating to riots that broke out after a disputed Kenyan election in 2007. Since then the platform has been used for everything from spreading information during the Haitian earthquake in January 2010 to dealing with snow removal in New York City.

Coincidentally, before Friday’s earthquake struck, Japanese volunteers had been working with Ushahidi to prepare for the possibility of an earthquake, says Patrick Meier, director of crisis mapping and new media at Ushahidi, a company founded to maintain the Ushahidi software. But Meier says the platform has become more sophisticated in the year since the Haitian earthquake. When that disaster hit, Ushahidi’s development team bore the brunt of the work on its own shoulders. “It was rough,” Meier says. Now it is much easier for people to create a version of Ushahidi tailored to their needs.

This year, Ushahidi has been used to help in Libya and with flooding in Australia. “Most of the time we don’t even hear about a deployment until it’s already out there,” says David Kobia, Ushahidi’s director of technology development, and Technology Review’s Humanitarian of the Year in 2010.

“Ten percent of this is the technology, and the other 90 percent is the people,” says Meier. “That’s truer and truer as the technology gets easier to use.”

To provide volunteer emergency support, Ushahidi has created a Standby Task Force—people all over the world who are trained, vetted, and ready to help with mapping all the information that pours in when an event occurs. The team now includes more than 300 volunteers.

Other Internet-based disaster-response services are following Ushahidi’s lead.

SparkRelief, which shares information during a crisis and lets volunteers find ways to help, began in Boulder, Colorado, to help victims of fires quickly find food and housing, and to coordinate people who wanted to supply these amenities. In response to the Japanese disaster, the nonprofit launched a programming effort to build a site to help earthquake survivors find housing. The resulting site lets people enter in their housing needs, and aims to connect them with those who can help.

Google also responded rapidly to the disaster, launching a web site designed to help locate people displaced by the earthquake and tsunami. Google operated similar sites for recent disasters including those in New Zealand, Chile, and Haiti.

Aside from direct efforts to share information about the crisis, social media sites are also using their pull to raise money fast. At the South by Southwest Interactive festival in Austin, Texas, tech companies have put together improvised fund-raising software and events. Hurricane Party, an iPhone app designed to help people organize spontaneous events, put on a fund-raising party on Sunday night along with Eventbrite, a company that sells tickets online. The Hurricane Party app let users spread the word quickly about where and when an event would be, and Eventbrite sold tickets for a donation of $10 or larger. The event raised about $10,000 for the Red Cross for Japan Relief.

The organizers of South by Southwest have also set up a website devoted to raising money for the relief effort in Japan, and are encouraging attendees to donate and spread the word through Twitter, Facebook, and other social sites. As of Monday morning, the site had raised more than $23,000 for the Red Cross.