Facebook was a derivative of prior social networks. Pirate's operation is a derivative of other financial business models, not necessarily a Ponzi. The early growth patterns are similar, rapidly building an increasing share of their respective markets.

Initial investment in either would return enormous profit (not the FB IPO). Whether it's through capital gains or a huge dividend, the result is the same; we're just accustomed to the "normal" pattern of dividends being paid after the explosive growth phase.

Literally any business could be loosely compared to a Ponzi. A startup begins, grows rapidly until it encounters competition or the limits of its market, then slows or stops growing. The difference is that finance doesn't actually produce anything to support itself with once it hits the limit.