Definition of a Ponzi Scheme: a form of fraud in which belief in the success of a nonexistent enterprise is fostered by the payment of quick returns to the first investors from money invested by later investors.
The problem I see with all of these articles about STEEM being a Ponzi Scheme is that the argument is missing one key element, which is that people who are scammed by a Ponzi Scheme generally give someone a lot of money expecting great returns. In the end much like the Madoff scheme, people are surprised the day they wake up and find that some knucklehead has scammed them of thousands of dollars of their hard earned money.
To date I personally have not invested that much of my own money in to STEEM so I'm comfortable with this not being a Ponzi Scheme.
So why are people calling it a PS? Likely because they want the price of STEEM to fall so they can get it cheaper!
People called BTC a ponzi scheme. I haven't really read too much into the transparency/trustworthiness of the devs much but, I have been having a little fun with the platform and plan to do some more OC creative posts. There are a lot of mistaken facts in this article and others like it. I like some of the apps and chat going on but, it seems like there is too much active key/owner key stuff going on IMO.
I'm still on the fence and checking it out.