During WWII there was information the allies had that they couldn't act upon. People died in air raids even when someone already knew it was coming. It was the legendary program of code breaking that let the allies read axis encrypted messages without their knowledge. Its level of secrecy was called Ultra in Europe and Magic in the Pacific.
I was wondering, what is today's equivalent of Ultra/Magic? What secret could potentially be so important that its existence should not be revealed, even through indirect action? I present this purely as a thought experiment, not a tinfoil hat conspiracy brewing session. One candidate quickly comes to my mind: factorization via quantum computing.
Imagine a system that could decode messages over any tappable communications channel worldwide within hours of transmission. What would that mean for foreign diplomacy, the War on Terror, the Arab Spring, or the Cyberwar between China and the US? If an encrypted message is cracked, especially one that used old codes or hardware, perhaps the eavesdropper would risk acting on the information?
This brings me to my actual point: There are unforseen ethical side-effects of technological progress. I think the researchers out there investigating superconductivity and quantum computing probably never think of how their discoveries could be used for spying on civilian dissidents, destabilizing foreign governments, and making a case for war. However, as soon as the research is close enough, what organization wouldn't attempt to build a practical quantum computer? Flame is good evidence that the state of the art can be advanced outside of academia.
My conclusion is you can't live your life worrying about this. I have faith that it's going to work out in the end, somehow. Breakthroughs in science and technology form a boundary layer that we can't see beyond. And I don't mean the singularity, which is the superlative form of this. It's simpler: I just can't imagine that Napoleon would have considered high-definition video chat to be anything but magic.
Postscript: Read Cryptonomicon if you haven't already!