pyramid schemes — also referred to as franchise fraud or chain referral schemes — are marketing and investment frauds in which an individual is offered a distributorship or franchise to market a particular product. The real profit is earned, not by the sale of the product, but by the sale of new distributorships. Emphasis on selling franchises rather than the product eventually leads to a point where the supply of potential investors is exhausted and the pyramid collapses.
http://en.wikipedia.org/wiki/Franchise_fraud
Seems like, under that definition, the question is whether people are paying you for the book, as opposed to paying you for the right to engage in the pyramid scheme.
Remember, copyright law gives you a right to exclude, but it does not absolve you of other legal obligations. For example, you can commit antitrust-like violations using a copyright (this is called "copyright misuse"). So if your scheme is indeed a pyramid scheme that violates the law, then copyright will not protect you.
That said, I'm just hypothesizing on facts I'm imagining, so obviously consult a lawyer with any real situations.