In our new book, Entrepreneur's Guide to The Lean Brand, Jeremiah Gardner and I tackle how relationships build passionate customers. In our view, products should fulfill a utility promise -- this functionality solves a that specific problem. But fulfilling the promise can only create 'satisfaction.' (Not always true, but generally.) It's the relationships between company and employees with customers that potentially creates 'passion,' which is required for scalable growth.

So how do you measure passion? Probably not in one particular way. Some combination of things like Net Promoter Score, Must-Have Score; social-media campaigns that measure participatory behavior; increase sharing of content; increase in viral-coefficient (OK for non-network effect business < 1!).

Early on, the best way to establish relationships is by meeting customers in person, in order to understand them deeply and develop empathy. Hypothesize 'what behavior can I expect from a customer with whom I've developed a relationship?' Measure whether that behavior is occurring.