It seems more and more like the Stuxnet computer worm was created by the governments of US and Israel to stop or slow Iran’s nuclear program. It’s significant because it’s a good example of how hacking can actually have a physical effect (thanks to SCADA networks), and that governments are realizing the power of computer warfare.
Takeaway for most people: Remember that you should never place unknown USB memory sticks in your computer, and realize that unusual behavior can be an indicator of an attack on your system.
http://www.nytimes.com/2011/01/16/world/middleeast/16stuxnet.html