"In fact, the way the metadata is ostensibly used to target individuals and groups NSA agents deem to be a threat is not dissimilar to how advertising targeting

"In fact, the way the metadata is ostensibly used to target individuals and groups NSA agents deem to be a threat is not dissimilar to how advertising targeting works. But that’s another discussion." This was an important takeaway, although in hindsight it's pretty obvious. Assuming (conservatively) NSA is approximately 5 years ahead of current commercially available technology, it seems there's quite a bit of headroom for targeted advertising methods to grow and get better.