During the biannual event called the Random Hacks of Kindness (RHoK), hackers worldwide develop software that can help identify and reduce risks from natural hazards.
It's a far cry from the darker side of hackers who recently disrupted the computer operations of companies trying to shut down WikiLeaks, says Christian Science Monitor.
During these events, hackers develop and improve tools aimed at helping emergency managers respond more effectively to disasters.
Craig Fugate, who heads the Federal Emergency Management Agency in Washington, had a potentially lifesaving item on his wish list: a tool people in a disaster-hit area could use to tell friends and relatives that they are OK.
Within 24 hours of Fugate's request, small groups of self-styled hackers produced two solutions, including a cellphone app called "I'm OK!", according to the Monitor.
That push in November 2009 marked the birth of RHoK, which saw its latest code-a-thon this month.
Among the fruits of this month's effort: A team of programmers in Chicago improved "I'm OK!" It now has a "not OK" function that shares location information so emergency workers can more readily locate and aid senders who need help.
"We are taking back the word 'hacking'," says Will Pate, with the World Bank's Global Facility for Disaster Reduction, who participated in the event from Toronto. "These are events where people are there because they care" about helping others.
The RHoK effort, founded by Google, Yahoo, Microsoft, the National Aeronautics and Space Administration, and the World Bank, has expanded from one gathering of a handful of hackers in 2009 to 21 venues across four countries in December. An estimated 1,500 specialists participated this year, the Monitor said.
One group designed a user-friendly Web "portal" for images from NASA's Terra and Aqua satellites and devised a way to break up the large image files to make it easier to ship them over the internet, it said.
The satellites create images so frequently that governments and aid organizations could quickly get an overview of the effects from a major flood or landslide and tailor their responses accordingly, says Christopher Gerty, an information-technology specialist at NASA who took part in the event.
All of the applications are open-source, meaning anyone anywhere can use and tweak the programs in exchange for making those tweaks available to everyone else. And the apps are free, although many of them are still early prototypes.
While some apps, such as "I'm OK" are designed for phones, others are designed to remain on the Web, where anyone with Web access can use them, says Deborah Shaddon, a technology specialist with CNA Insurance Company and organizer of the Chicago event.
Random Hacks of Kindness, she says "is drawing people in with the message of trying to do good and taking your skills as a technologist and saying: This is what we can do" to help disaster mitigation and response efforts globally.