Often, secrecy is considered to be a form of power: if you and only you know stuff, you're at an advantage. But, as General Stanley McChrystal explains in this video, that isn't always the case.

McChrystal started fighting al Qaeda in 2003, and he considered his secret information to be the lifeblood of his operations. But, over time, things changed—and he realised that keeping important information classified was actually misguided and counterproductive. Watch the video to find out why. [TED]