I just remember Novak talking about this thing back when it first "broke"... and even he was sorta mystified by the whole thing.
I remember him saying something to the effect of "Of course Valerie worked for the CIA... everybody in DC knew that. It was an open secret."
Wilson outed her in his own book for crying out loud! Wilson didn't seem to think it was a secret either. He was getting it ready for printing when the story broke!