Okay so here is a new(er) question.

I did some research, and figured out what a ponzi scheme is. Its basically a pyramid scheme where you don't tell the people investing that they are in a pyramid scheme, right?

So pyramid schemes are not fraud, but are still illegal. This means they are illegal even when using bitcoins, or other not-legal-tender currencies, correct? If so, a LOT of websites are illegal...

Anyways, here is my question: What exactly is the real difference between a bubble (not illegal) and a pyramid scheme (illegal)?

I mean, I could create some fake currency (can a currency really be fake?) on a website backed by some mysterious (and basically useless) commodity, and let people bid on it and sell it to each other. I could then create a bunch of fake accounts (can an account really be fake?) on my own website and bid up the price myself. Knowing how things work, people will probably buy them just because their price has been increasing. Is this a pyramid scheme (illegal), a ponzi scheme (illegal), or just a bubble (not illegal)?

I ask because I want to start one of these sites like http://stockvm.com except running on bitcoin, and where it actually works. You think this is a bad idea?