Glad to see that this thing is being a huge monkey wrench in the gears. However, it illustrates the damage that could be unleashed by competent programmers working with the full resources of a nation's intelligence services behind them, i.e. somebody could do it to us too. From what I've read about the Stuxnet worm, the team who wrote it (its complexity and knowledge of industrial processes makes it almost certainly a collaborative effort) was very meticulous in making it target only systems that met a particular profile. One of its triggers is detection of industrial motors running at a certain frequency -- the range expected from centrifuge motors. This discriminating behavior was due only to the goals of its creators. Malicious use of the concept could wreak havoc on anything from traffic lights to operating room ventilators. Siemens' PLCs are used everywhere, along with similar equipment from competitors like Honeywell.
It would not surprise me at all if Siemens itself was a clandestine participant in the creation of this worm. Their equipment and software in Iran was obtained via black market, so it's not like they're at risk of losing a legitimate paying customer.
