Sam Lawrence has this great blog post on 9/11 and the social software movement. Lawrence said, "Getting to who and what we needed faster was critical in this time of need. The companies didn’t matter, the people did." He sees 9/11 as a moment of change for social media. Lawrence said, "We commented, we connected, we asked why. News broke faster over blogs and email than traditional media. At the same time our government quickly learned that their systems weren’t built to connect the dots the way we really needed them to."
I learned of Lawrence's post from Shel Israel's Twitter feed. I highly recommend both.