Okay, I dislike anything like self-promotion, but PC World is being very kind here:
Captain Ronnie Young of the United States Air Force says that Craigslist and Google Earth, both popular freebies, saved lives during the Hurricane Katrina disaster. "Just because it's free, that doesn't mean it's not up to the task of doing great things," Young says.
The eureka moment came to Young days after Katrina devastated New Orleans. As a senior intelligence officer with the 347th Expeditionary Rescue Group, his job was to help helicopter pilots locate people who needed rescuing. On a tip, Young went to Craigslist and began scouring hundreds of postings on its New Orleans message board — pages of messages left by worried relatives and friends inquiring about missing loved ones.
Young remembers reading postings pleading to any rescue worker to save family members and friends who were either too old or too sick to stand on their rooftops and wave down a passing helicopter.