Osama's replacement

It is somewhat surprising to me that al-Zawahri, the man often cited as Osama bin Laden's number two, has not assumed immediate control, but according to at least two sources (here and here), Saif al-Adel, a long-wanted al-Qaeda military chief, is in temporary operational control.  Alas, killing bin Laden did not decapitate al-Qaeda, as many American wistfully dreamed.  Violence breeds violence.