Quirk: If 9/11 defined the last decade, will the Arab Spring define the next?

In a memorable moment in The Social Network, Mark Zuckerberg says of some rivals, who were claiming he had stolen their idea, “If they had invented Facebook, they would have invented Facebook.”  I’m inclined to say that if the Arab Spring were another 9-11, then there wasn’t a 9-11.  Events that have such enduring, widespread, and obtrusive consequences for everyday life, as well as for the preoccupations of public officials, do not occur at a rate of one per decade.

What is most striking about the consequences of the Arab Spring, at this stage, is their extraordinary uncertainty.  How many revolutions will occur, and where?  What kinds of governments will emerge?  The answers (or the process of learning the answers) could define the next decade.  On the other hand, the whole development could amount to marginal changes in 2-3 moderately important countries.