There have been an increasing number of cyber attacks in recent years. Not long ago Google blamed China for hijacking gmail user accounts. Iran's Nuclear program was a target of a stuxnet virus, now a modified version has been wreaking havoc in Europe. And most recently, US is saying that China and Russia are actively targeting sensitive technology and military information via cyber hacking.
http://www.reuters.com/article/2011/11/ ... FX20111103
We are pretty much in the midst of a ongoing silent war. This is extremely concerning since our economy is powered by the global web. If a group can pull off a 9/11 version of a cyber attack, it will be devastating to the world economy.