AQ's Size

A few hundred, or tens of thousands.

"...Hirsh'sNewsweek article said that the intelligence community “generally agrees that the number of true A-list Al Qaeda operatives” at the time of 9/11 probably between 500 and 1,000, most of them in and around Afghanistan...."

http://www.harpers.org/archive/2006/07/sb-al-qaeda-new-members-badly-needed-1...

"In addition to Al Qaeda’s Pakistani-based high command and the hundreds of other operatives in its core organization, “Al Qaeda Prime”, Osama bin Laden’s terrorist syndicate includes dozens of affiliates located in over sixty countries throughout the world. Although America’s post-9/11 campaign appears to have eliminated most of Al Qaeda Prime’s operatives within its former stronghold of Afghanistan, the two most crucial targets have eluded the superpower. The syndicate’s operational director Ayman al-Zawahiri still controls Al Qaeda, issuing regular communications to the world at large and strategic guidance to the syndicate in private, while Bin Laden remains the indomitable symbolic leader of this anti-American insurgency. Additionally, many of the Al Qaeda Prime operatives who were sent from Afghanistan and Pakistan to other areas of the world remain at large. This dispersed group constitutes an unknown number of terrorist agents recruited from the tens of thousands of trainees that filtered through Al Qaeda’s camps, located either in Afghanistan prior to 9/11 or in Pakistan after 9/11. Following America’s disastrous public relations fallout from the Iraq invasion, the 2007 U.S. National Intelligence Estimate’s classification of Al Qaeda being “as strong as ever” suggests that Al Qaeda Prime may in time regenerate its depleted membership with a surge of new recruits motivated to join Bin Laden’s anti-American insurgency. Furthermore, nearly a decade after 9/11 Al Qaeda’s numerous affiliates remain largely in tact, as evinced by such catastrophic terrorist attacks as the Mumbai Massacre executed via the Pakistani-based affiliate Lashkar-e-Taiba at the behest of the Al Qaeda command sub-unit known as the “313 Brigade”. Perhaps most troublesome, Al Qaeda Prime has fortified its base in Afghanistan and Pakistan with the large percentage of Taliban operatives allied to Bin Laden under the leadership of Mullah Omar and the “Mehsud” coalition, along with affiliates like the Haqqani and Hekmatyar networks. The total membership of this umbrella organization that Bin Laden and Zawahiri have cobbled together numbers in the tens of thousands and provides Al Qaeda Prime with a global reach unmatched by any other terrorist network..."

http://www.binladensplan.com/AQ_s_Size.html