Koster doesn't have slides up yet, but in a nutshell he says that games are about training the intuitive part of the brain. And to do that we look to mathematical/computational complexity. Games in the NP and higher complexity realms are very engaging. I heard all my CS professors shouting with exuberance. He used Karp's 21 NP-Complete problems as a reference, and boiled down every successful and fun game to some form of an NPC problem. My question then: is any game modeling an NP-C problem reducible to SAT?
Schubert pretty much convinced me that today's MMOs need solo aspects.
And Sebastien de Halleux from Playfish convinced me that I should be making Flash games.
Now to catch up on all my work... (and play Aion)