At the idea stage, through interacting with customers and running experiments, you validate that you have the right customer profiles and understand the problems they face.
At the MVP stage, you iterate on the product, run experiments on functionality, perform usability testing, and try to nail the core value proposition for the market segment. You continue to interact with customers to test that you are building the right product, learning more about their problems and learning how you will market, sell, and deliver your value to them.
Product-market fit is a continuation of experimenting and growing the product to find early mainstream passion and to establish the correct positioning and messaging.
In the customer acquisition stage, you’re validating the conversion funnel, testing acquisition channels, and measuring return to ensure you have a functioning business model.
The final stage to scale is learning how to get out of the way. To scale, organizations must adapt. They must learn how to execute efficiently, while continuously learning and continuously improving.
But, of course, the devil is in the details.