There is no reason, in a virtual goods model, that larger audience sizes require thinner margins. Players choose games based on how much fun they are having and what they can play socially with their friends - not the pricing on individual items.

Also, the author states "You think they're going to justify a $50 billion market capitalization through banner ads? Are you kidding me?".

This has nothing to do with Zynga and ignores Facebook Credits, which give Facebook a 30% cut of all the revenue on the platform. I'm pretty sure this author has never heard of them.