Now that you know what a Ponzi scheme is, I will tell you how and why Facebook is like a Ponzi Scheme. The argument is similar to how Paul Graham describes that Yahoo was a ponzi scheme in 1998.
Facebook posts huge revenues. In fact, recent reports are that Facebook is very profitable. This boosts both their respect in the world and their valuation. However, these returns, while real, are unsustainable. They exist and are sustained in the same manner that Ponzi schemes are. Facebook is a Ponzi Scheme.
Have you ever bought a Facebook ad? I have. I have talked to many, many people who have. We have spent hundreds, many have spent thousands or even more, experimenting with Facebook ads. They are worthless. Nobody ever looks at them, and nobody ever clicks on them. I just talked to someone who was trying to promote a book. He found it cost him over $100 in ads to sell one book. Moreover, as you increase your ad spending, people get used to the ads and just ignore them. So, your already low click-through rate plummets even further.