Bit more data on the FTC's opinion:
http://www.ftc.gov/public-statements/1998/05/pyramid-schemes
Incidentally a pyramid scheme almost took down the Albanian economy and sparked the 1997 rebellion.
I suspect BTC investors are a little more sophisticated, but given the pseudo-anonymity behind cryptos, I wouldn't be surprised if something like this doesn't wreak a respectable amount of havoc in the future once cryptos are more widely held.
PS: If the site author's reading this, I'd start hitting the 5x5 stronglifts hard with a good bulking nutrition regime. You really want to hit the ground in federal prison with a size advantage. So I'm told. Can't wait for the AMA.