Inside Google reports that links to charity and housing websites on Google’s Katrina page have the rel="nofollow" attribute. Google’s own services such as News don’t have nofollow attribute. Inside Google asks, "Is this really the time to be playing this game?"
Nofollow stops the target page from getting PageRank. There are various reasons why Nofollow sucks but why Google is using it here is beyond me. The use of nofollow indicates that Google doesn’t want people searching for Katrina to find the Red Cross website but would prefer people searching for Katrina to download the Google Earth application.