By the time that product is ready to be distributed widely, it will already have established customers.

We must learn what customers really want, not what they say they want or what we think they should want.

Progress in manufacturing is measured by the production of high quality goods. The unit of progress for Lean Startups is validated learning-a rigorous method for demonstrating progress when one is embedded in the soil of extreme uncertainty.

The minimum viable product is that version of a new product which allows a team to collect the maximum amount of validated learning about customers with the least effort.

At IMVU, the cost of customer acquisition through our five-dollar-a-day AdWords campaign was less than twenty-five cents. Our revenue from those same customers was more than a dollar.

If we do not know who the customer is, we do not know what quality is.

Learning is the essential unit of progress for startups.