In some ways, Matrix resembles other data-driven counterterrorism initiatives started since the 2001 attacks. The Pentagon's controversial Terrorism Information Awareness program also sought to use personal data in new ways, but on a far larger scale. The idea, started by retired admiral John Poindexter, was to create a global data-surveillance system that might find subtle signs of imminent threats. Lawmakers sharply limited the program's funding several months ago, and now some intend to shut it down.

A Justice Department document from early this year describes Matrix as an effort "to increase and enhance the exchange of sensitive terrorism and other criminal activity information between local, state and federal law enforcement agencies." Matrix organizers met several times with Sen. Bob Graham (D-Fla.), while he was head of the Senate Intelligence Committee, to discuss the system's development.

The Matrix project began soon after the 2001 attacks. Seisint founder Hank Asher, a wealthy data entrepreneur, called Florida police and claimed he could pinpoint the hijackers and others who might pose a risk of terrorist activity. "Asher says, 'I'll develop this for free,' " [Phil Ramer] said.