Seems like the system may have failed and made it seem like all of the tickets were sold out in two minutes. Apple is following up trying to sell off the unsold tickets without re-opening the sale to the public.
Just a theory.
I think that the payment side of the system failed, but the side of the system that keeps track of inventory was decrementing the inventory with every purchase attempt.
Who'd have thought they'd need a robust sales system for $1600 tickets being made available to a developer community?
I understand when their servers go down during an iPhone launch while trying to verify your contract status with AT&T or Verizon or Sprint. But WWDC sales volume has to be far less.