Twelve Years after 9-11, How Big a Threat Is al Qaeda?

Should we be afraid of al Qaeda? Officials in Yemen say they thwarted a plan by al Qaeda to seize a major port and kidnap or kill workers there. It's not clear how real that threat was. But the news came days after the US and Britain closed embassies across the Middle East and North Africa, fearing a terrorist attack. Meanwhile, hundreds of prisoners, including al Qaeda operatives, have escaped from prisons in Iraq, Libya and Pakistan. How have power vacuums in places like Iraq, Syria and Yemen created openings for al Qaeda to grow? Two years after the killing of Osama Bin Laden, how powerful is al Qaeda?