But my biggest problem, I quickly realize, isn't what's happening on my laptop screen. It's what's all around me at the café — customers using their laptops, phones, and tablets. All of these devices double as video and still cameras, and each of them could be used to spy on me. My expert guides warned me that the biggest threat to my privacy today would be the inadvertent snooping of my fellow citizens. Given the ubiquity of smartphones and other location-aware gadgets, and the ability of the NSA to cull and parse the data that comes out of those devices, we've become our own distributed network of unwitting spies, one whose collective reach is nearly infinite.