The topic of this thread is the bond, not Bitdaytrade itself (which probably is also a scam, but not a ponzi). This 3% per week "bond" had all the hallmarks of a ponzi and the same predictable and predicted outcome as a ponzi.
It's nothing like a ponzi. The characteristic of a ponzi is that the underlying business is kept hidden and actually does not exist; in this case the business was specified and did exist (whatever problems it had).
Of course, this was one of the reasons the bond was so attractive. An actual website made it seem so legitimate.