Ayman al-Zawahiri has replaced Osama bin Laden as the head of al Qaeda. Lawrence Wright explains the significance:
Now that bin Laden is gone, the challenge for Zawahiri will be to keep non-Egyptians in Al Qaeda. Members pledged their loyalty to bin Laden personally, not to the organization, so a new round of declarations will have to be made, providing Zawahiri an immediate test of his popularity.
The Dish 