Ah, that is a great post... but the real gold was in the comments I think... the bit that convinced me that it isn't a Ponzi scheme is that there is money coming from outside... not just from new people buying into the platform. The Miners are producing Steem (30%? 20%?) which goes into a pool and the people get to decide how that gets divied up... with those that have invested in the platform (either content or money) having more weight in that decision.