9% of online Americans made donations on the internet to relief efforts and 7 million set up their own hurricane relief efforts using the internet. In addition to using the internet to respond directly to the crisis, 50% of online users sought out news and information online.
Since the beginning of 2005 the number of Americans who say they have ever made a gift online has increased by 53%. Now there are 26 million online donors each year vs. 11 million estimated at October 1, 2004.
You can find this report by Pew Internet at http://www.pewinternet.org/pdfs/PIP_Katrina.DateMemo.pdf