Slate.com has a short and interesting article regarding the use of data mining and social network analysis by the National Security Agency in its efforts to hunt down terrorists and terrorist cells. Social network analysis is used by the NSA as an effective way to establish links between known and potential terrorists.

From the article —

Last Thursday, USA Today reported that the NSA has been collecting the phone records of millions of Americans. The agency is apparently using “data mining” techniques to scour these records for connections between terrorists. According to an intelligence official interviewed by USA Today, the NSA is analyzing this data using “social network analysis.” What’s social network analysis?

A technique to map and study the relationships between people or groups. The basic concept of the social network is familiar to anyone who has used Friendster or played Six Degrees of Kevin Bacon. Social network analysis formalizes this parlor game, using details about the network to interpret the role of each person or group.

In a basic analysis, people are seen as “nodes” and the relationships between them are “links.” By studying the links—in the case of the NSA program, telephone calls—it’s possible to determine the importance (or “centrality”) of each node.

You can read the entire article @ How the NSA Does “Social Network Analysis”.