A UNO prof used .Mac to get his data and students through Katrina. I long ago gave up .Mac (too much money for what it offered me) but though my sites hosted by 1and1 and my blog I was able to keep in touch with students and faculty. Technology really came into its own with regards to humanitarian needs last August/September.
Facebook also proved useful when cell phones and Webmail went down. We posted where we were and our alternate contact info.