NYT's Ben Hubbard, on al-Qaeda's second wind:
What links these groups, experts say, is no longer a centralized organization but a loose ideology that any group can appropriate and apply as it sees fit while gaining the mystique of a recognized brand name. In short, Al Qaeda today is less a corporation than a vision driving a diverse spread of militant groups.
“Al Qaeda is kind of a ready-made kit now,” said William McCants, a scholar of militant Islam at the Brookings Institution. “It is a portable ideology that is entirely fleshed out, with its own symbols and ways of mobilizing people and money to the cause. In many ways, you don’t have to join the actual organization anymore to get those benefits.”