Early in the life of a business, the product manager (often a founder) plays both the role of the PM and the PMM. Over time, the startup’s growth demands a more specialized role.
Many times, the PM builds the product as quickly as possible to establish product/market fit. In contrast, the PMM answers critical questions about the company, product and market to ensure the product sells.
What are these critical questions? I found an excellent list in Kotler on Marketing that I adapted for startups. How many of these questions can you answer about your business?