"... Ponzi's original scheme was based on the arbitrage of international reply coupons for postage stamps..."
^"arbitrage" now doesn't this sound familiar? why wouldn't the usual suspects use every trick in the book? ~ especially in a new unregulated market? ...o rly? lol

The Brazilian bitcoin ponzi BitcoinRain (already collapsed) promised their clients something like 9% return per month, minimum. The founder claimed that he could get that much by doing arbitrage between exchanges.