how to calculate when a network marketing company will begin exponential growth?
Dr Charles King has done some research that suggests that companies in
the US reach exponential growth at around $50 million turnover why is
this a critical point and what exactly causes this to happen? I know
that the company must become established and have payment systems
finalised but there must be other factors in determining the critical
mass necessary to go exponential. Particularly interested in applying
this to the UK and other countries in order to predict exponential
growth as accurately as possible.

I remember reading an article about growth stages in the network
marketing company at the Knowledge@Wharton
<http://knowledge.wharton.upenn.edu>. Try searching there.