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The exercise did demonstrate that damage was, in fact possible. However, nothing as bad as dreaded cyberterrorism related judgement day that government officials and the media have perpetuated since September 11.
Many of the suggested means of attack, phone networks, automated payment systems, etc, were vulnerable, but nothing so open as to cause irrepairable national damage.
The Gartner group has released the results are they are available here.
The Register has an excellent summary/analysis of the report.