"We've got to stop the flow of water," Seventh-day Adventist disaster services director Charlene Sargent told the Los Angeles Times two weeks after Hurricane Katrina struck land. She wasn't talking about broken levees, but about the truckloads of donated drinking water. "If you took everything we got this weekend and put it in New Orleans," she said, "it would raise the elevation so it wouldn't flood again."

In the first week after Katrina, U.S. charities raised over $500 million—more than 2.5 times the cost of the Louisiana Purchase, adjusted for inflation. Within three weeks, American giving surpassed $1 billion, and in less than four, it had surpassed the to-date gifts for victims of last year's Asian tsunami. And that was just what got on the books—it doesn't count the Houston families who rushed to the Astrodome offering housing and food, nor the kindhearted Good Samaritans who loaded up whatever they could find and drove as far into Louisiana as they could.

The Katrina donations may herald a new revolution in giving, said The Christian Science Monitor. "People want to participate in a charity walk or hand out sandwiches at a shelter," Stacy Palmer, editor of The Chronicle of Philanthropy, told the paper. "They want to take their involvement way beyond just writing a check."

Organizations report ethnic minorities, young people, and others giving at rates inconceivable a few years ago. And donors are wanting to call the shots, too: World Vision doesn't respond to U.S. disasters, but had so many contributors banging down the door that it raised $4 million for aid and school supplies in less than a month.

The Washington Post personal finance columnist Michelle Singletary wonders if donors are being trained to respond ...