In a Ponzi Scheme, early investors are paid returns based on the investments of later investors.

So who are the "investors" receiving returns? If we're talking about ad buyers, they're not being paid anything worthwhile regardless of when they invested, early or late. If we're talking about shareholders of Facebook, early shareholders aren't receiving returns based on later shareholders.

Perhaps describing Facebook as a bubble might be more apt. But it's pretty strange that this guy spent all this effort to define what a Ponzi Scheme is only to mis-describe something as a Ponzi Scheme.