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.

As you consider building your own minimum viable product, let this simple rule suffice: remove any feature, process, or effort that does not contribute directly to the learning you seek.

Nowadays people talk about PayPal's founders as prescient geniuses who would inevitably change the world. It was, however, not so obvious that PayPal would taste its first major success by helping people sell Beanie Babies on eBay. But they had a vision, a hope, and the perseverance to try multiple iterations until they got it right.

Innovation is a bottoms-up, decentralized, and unpredictable thing, but that doesn’t mean it cannot be managed.

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.

I would say, as an entrepreneur everything you do - every action you take in product development, in marketing, every conversation you have, everything you do - is an experiment. If you can conceptualize your work not as building features, not as launching campaigns, but as running experiments, you can get radically more done with less effort.

Entrepreneurship is not really building a product, it's not having an idea, it's not being in the right place at the right time. It's fundamentally company building.