If I understand correctly, a pyramid scheme is something like when you try to convince me that 2 people will send me a dollar if I agree to send you a dollar. Is bitcoin really like that? In what sense do I have to send someone "already enrolled" in the scheme a dollar to get my two dollars?
It's not a pyramid scheme in the exact sense, but Bitcoin's more valuable with a wide subscriber base, and early adopters have a large advantage in terms of acquiring portions of the Bitcoin space cheaply. The changes in the investment-to-returns ratio over time that these pressures produce do end up looking a lot like a pyramid scheme's in the case where Bitcoin fails as a currency, even though you can make that investment in GPU cycles rather than dollars.
If it succeeds as a currency, of course, that curve ends up looking more like what you'd see in a g...
There seems to be quite a bit of a Bitcoin interest around here, with several articles about it already: [1 2 3 4 5 6 7]
I propose that links and generic Bitcoin comments should be posted here, instead of making a new discussion thread for each interesting article about the subject.