Only 5 percent of entrepreneurship is the big idea, the business model, the whiteboard strategizing, and the splitting up of the spoils. The other 95… - Eric Ries

The rules that govern the sticky engine of growth are pretty simple: if the rate of new customer acquisition exceeds the churn rate, the product will grow. The speed of growth is determined by what I call the rate of compounding, which is simply the natural growth rate minus the churn rate.

Getting a startup’s engine of growth up and running is hard enough, but the truth is that every engine of growth eventually runs out of gas. Every engine is tied to a given set of customers and their related habits, preferences, advertising channels, and interconnections. At some point, that set of customers will be exhausted.

the paid engine of growth is powered by a feedback loop. Each customer pays a certain amount of money for the product over his or her “lifetime” as a customer. Once variable costs are deducted, this usually is called the customer lifetime value (LTV). This revenue can be invested in growth by buying advertising.