World's Tweets Tracked by CIA in McLean Industrial Park

In an anonymous industrial park in Virginia, the CIA is following tweets -- up to five million per day.

The idea is that when rebels, militants, activists or diplomats broadcast information on Twitter or elsewhere, America's spies scoop it up.

At the agency's Open Source Center, the analysts the CIA affectionately calls its "vengeful librarians" pore over all forms of social media in many different languages, from all over the world.

The CIA studies and cross-references the material with clandestinely intercepted information to form a snapshot of anything from the mood in Pakistan after the Navy SEAL raid that killed Osama bin Laden to whether a Mideast nation seems ripe for revolution.

The CIA facility was set up in Virginia in response to a recommendation by the 9/11 Commission, with its first priority to focus on counterterrorism and counterproliferation.

The AP estimates there are several hundred analysts tracking the world's tweets and Facebook updates in McLean -- the exact number of employees is classified.