A Ponzi scheme is one where the schemer uses later investments to pay off the earlier investors.
From the
land claim Q&A, I drew up a list of features they are promising, but haven't implemented yet:
3D Models/Objects: Beacon, Claim licenses
Outposts:
Outpost crafting systems
Outpost modules:
habitation
armory
refinery
hydroponics
storage
medical
Automated Defense drones
Planetary Weather
Sandstorms
Electrical storms
winds
snow
other
Planetary Geophysics:
Earthquakes
Motion Detection Alerting System
Claim registration system
Space Criminal System
Destruction of Claim Posts
Piracy
Theft
UEE Protection system, UEE Patrols
Dedicated Mercenaries
Private Defense contracts
Land designation systems.
Available for Claim
Reserved
National parks
Wildlife Refuges
Nature PReserves
Industry:
Mining
Commercial Production
Retail outlets
Analysis:
Core samples
Seismographic surveys
They are very clear that "These claim licenses are being made available for pledging to help fund Star Citizen’s development." In other words, they will use the money to fund the development of features.
Now, if they're using the the money from this sale to pay for the development of previously-promised features, then what you have is not a Ponzi scheme, but the incorporation of Ponzi elements into a different funding scheme, a Ponzi-like, if you will (or a Ponzi-like-like), specifically:
Announcing and selling new features to pay for the development of already-promised ones.
Crowdfunding implicitly monetizes feature creep; by having a continuous funding model, they are continuously creeping.