Well, I agree that it Probably IS a Ponzi, but at this point it is all speculation. I have heard of no one that has not been paid, and I have gotten everything I have submitted back times 2 (But I am only using coins that have relatively low value) but free is free. So no harm at this point. Only submitting 50% of profits gained until they up and run..
You got paid in the expectation you would make posts telling people how you doubled your money which in turn would encourage others to deposit.
Obvious ponzi is obvious! There is no other explanation.