The NSA data-collection story has prompted a lot of reporting about “metadata” – information about communications between individuals. As the FT has reported:
The practice was revealed by The Guardian, which published an order – signed by the secret Foreign Intelligence Surveillance Court – instructing Verizon to give the NSA the metadata, or information logs, for the calls “on an ongoing daily basis”.
Call logs really matter. Even if you cannot hear the calls, metadata – knowing who called whom – is massively important. It allows you to build a picture of who knows whom and how well. This sounds trivially true, but computing power means it’s extremely easy to pull out this data in real time and in great detail. And if you spot a suspicious group, you can then get another warrant to listen in on their conversations.
Here is an example: I’ve put my Facebook account details into a piece of analytical software – and, 10 seconds later, this is my life:
This is a map of who my friends are based solely on knowing which of them is friends of the others. Nothing else. Just Facebook friend lists. It has worked out that the big clusters are groups of people who know one another – so probably have something in common. The ones at the centre of the packs know everyone else around them, and those at the edge are more peripheral.