Ha, didn't know about Ponzicoin. I don't know if something can be a Ponzi scam if the people were adequately informed lol. Let's see, according to wikipedia
A Ponzi scheme is a fraudulent investment operation where the operator generates returns for older investors through revenue paid by new investors, rather than from legitimate business activities or profit of financial trading.
And fraud is "deliberate deception to secure unfair or unlawful gain". So, if there was no deception on the part of the creator then I don't think it is actually a Ponzi scheme!
While it is not "fraud" because the terms are clearly stated, it is also not a "legitimate business activity" because the whole business plan is to profit off of those who just joined.
Other than this, there is no other source of profit or revenue to be generated and unless the creator decides to conjure up a unlikely alternative revenue stream, this is one of the most transparent Ponzi schemes ever.
Having said that, I now worry if scam artists will implement these ideas.