system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If the NSA is recording every single email and/or phone call in the world, how can they analyze so much data?

Surely computers can't do 100% of the work, right? Do they have such a badass computer that it would understand spoken subtext in a phone call? How do the people that work for NSA know where to look in so much data?
gpt
First, they aren't doing that.

What they do is record phone *records*. As in who called who and when. This is useful because if they have a bombing and then capture a suspect, they might look at the records and see that they called two numbers the evening of the bombing but got one incoming call. They then look at the incoming call's number and see that it has almost all outgoing calls, at regular intervals to a set of five numbers. This indicates that the caller was giving orders or instructions.

So they go to a judge with a security clearance and say "We think there is good reason to tap these lines because we think it is a terrorist cell, and future attacks will soon be ordered through this number." And usually that judge will issue that warrant, because usually they have good reasons to ask for it.