Bruce Schneier on recent Snowden revelations:

As fascinating as the technology is, the critical policy question—and the one discussed extensively in the FirstLook article—is how reliable all this information is. While much of the NSA's capabilities to locate someone in the real world by their network activity piggy-backs on corporate surveillance capabilities, there's a critical difference: False positives are much more expensive. If Google or Facebook get a physical location wrong, they show someone an ad for a restaurant they're nowhere near. If the NSA gets a physical location wrong, they call a drone strike on innocent people.

This is a reaction to this post from Glenn Greenwald.