When a company files to go public it has to lay out in black and white the biggest risks that face the firm. What could kill it? What could undermine its business? Wipe out all its investors' money? Executives are required to reveal this by law.
Traditionally, intelligence agencies have relied on top-secret information to track changes in other countries. But wiretaps and secret intercepts didn't help U.S. officials predict the Arab Spring that has brought revolution across the Middle East and North Africa.
In hindsight, officials say there could have found some clues about what was about to happen if they had read open sources more closely. Now they are searching for systematic ways to do that.