Seth Godin has as good and short a description I’ve seen of the curves of product sales. The four curves of want and get
Basically curve A is what everyone wants but rarely gets, Curve B shows a spurt of early adopters then hardly anyone else. Curve C shows the most realistic success curve which we should generally speaking plan our finances around and finally curve D which is essentially the failure curve.
These things are very important for us bootstrappers as we we need to be able to plan our funding/finance accordingly. I think it is best to plan for C. Obviously if you plan for D, why start at all. This is why it is so bad to fund with your credit card, because unless you hit curve A, the credit card will kill you before success hits in curve C.
Curve B is interesting. Seth talks about this as what happens if you a fan group who all buy your stuff immediately. Then no one else does.