So is he saying that he is unsure of the capability and valuation of Facebook based on Zynga's business model? This point still doesn't make sense in regards t

So is he saying that he is unsure of the capability and valuation of Facebook based on Zynga's business model? This point still doesn't make sense in regards to investing in Facebook if he is talking about the product being sold is software rather than virtual goods. One company that uses the platform has an unsustainable (according to the author) business model - therefore the company hosting the platform has a problem as well? And if the point does make sense, the author is certainly leaving a whole lot of his reasoning and explanation out of the actual article.