Even though the WWE is a big name, it seems that Saturday night's a cursed night for NBC, as they couldn't sell the time. Very few people watch TV on Saturday night, and if they do, they either watch CBS, Fox or ABC (or even the UPN or WB stations when their networks are off). It seems the viewers ignore NBC like the plague.
Has the other "Big 4" networks have any trouble with their Saturday ad inventories? Don't think Fox has trouble, with their die-hards "Cops" and "America's Most Wanted".