Collect telephone numbers for billions of U.S. calls, load the information into super-fast computers and you can start building a map of connections revealing patterns or oddities to help spot a terrorist.
The U.S. government’s primary electronic surveillance arm, the National Security Agency, is doing just that -- vacuuming up U.S. phone records and, at least in certain circumstances, analyzing them to develop leads that authorities can pursue to identify and stop terror plots.
