This is kinda where the "big data" conspiracies lose me. I maintain databases for a living, and the thing I constantly going around explaining to people is that

This is kinda where the "big data" conspiracies lose me. I maintain databases for a living, and the thing I constantly going around explaining to people is that giant piles of unstructured data does not actually correlate to intelligence. Even if you theoretically were able to collect the voice recording of every human conversation happening between every human on Earth, actually parsing or using that information proactively is just not feasible. So I think people are being a bit unrealistic about the extent the agencies can even use the massive amounts of data they have.