Matrix multiplication means picking up where multiple factors can be combined to produce a high score. It can analyze threat = capability x intent. I think this approach can be used as much by the individual trying to get a handle on reality (multiply news by what you know is possible) as by a massive organization (crunch data streams to find exploitable juicy bits).
If you think this way you will be paranoid. But, if you just want to imagine where things can go if they get even worse than they are now, say if unlimited resources are deployed by utterly immoral actors, it can be useful.
For example, without formal training I came up with the above threat equation. After typing the equation into Google, it turns out that it is correct and part of formal risk/threat assessment calculations. I figure that's because it is common sense.
Look. The entire data stream starting from the time a Kinect is plugged into electrical power can be automatically saved forever in a quiet data center.
XBox+Kinect is a very powerful listening device because of its smarts. It can download a program or search parameters and seek high-quality data, such as a conversation with a certain person's name in it, and filter it before sending it upstream. It can also compress a raw feed and gradually upload it over time.
So if anyone ever does something criminal or suggestive, like maybe your child has a party and someone does drugs in the living room, that data can be silently tagged and stored without any human's knowledge.
Any of your computers, or any computer ever in your vicinity throughout your daily life, or the lives of other people, can do the same thing. Just silently record at all times. There are too many ways it can be done in software. Free apps, buggy malware, browsers..
All phones, networked hardware, your car's On-Star navigation system and black box, can be additional channels.
Years later, if someone wants to find something on you they just make a mining query.
Queries can ultimately matrix multiply all locations x all channels x all individuals x all conversations files or positioning data.
Such as any conversation that mentions a target name or keyword ever held in front of anybody's XBox, personal laptop, tablet, wall phone, mobile phone, desk at work in any company. If you ignore any difficulty associated with processing/telecom/power/time capacity you will understand that rather than simply being "overheard" it is like you are leading your life by crawling over a jungle-gym moving from one data capture point to another. Your life over time and space, and those of all people with whom you interact, together become an immense transparent crystal object that can be observed at one's convenience from any angle.
Matrix Product: (exploitable output, or the threat)
Forget trying to end-run around the NSA, there is no point. But worry about other actors.
The U.S. data will be privately owned and controlled by other actors.
Any big company or country has a chance at subverting these streams and building their own global capacity.
A criminal organization could pressure a Verizon sysadmin.
The captured data does not have to go to court. It can be shown to someone else, or to you in order to embarrass you into tilting you towards a given course of action, for example if a target was shown video capturing an infidelity. The actor can dial in any degree of formality, truth or fairness.
Data that might have saved you (such as data proving innocence or entrapment) can be deleted, ignored, or modified in whatever private data center it is stored.
Parallel construction means all of this dark activity, a dark war against humanity, can be kept in the dark, but leveraged when some other expedient is selected.
Once you or someone many steps removed who you don't even know has been targeted or an annotation has been made, all past and future activity can be scheduled for heightened investigation, including active installation of subversions to improve the data feed.
It can be quite impersonal, like a game of chess. And there is no way to remove your tag.
Since tangential conversations and proximity drive data insights, "living with sincerity and honesty" is irrelevant.
One might hope that automated moral agents (strong AI) might one day swing things in the other direction, but they don't exist except in science fiction at this point and anything close to it is owned by the organizations doing the collation.