The product management is the critical role in a tech company. It is also what perform the function of marketing in a young company until you get to a much later, more mature stage.
Marketing is a strategic function about delivering customers what they want. It isn’t a jazz hands and rubber chicken and t-shirts. It is the heart of successful companies–Unilever, Coke, Apple, Google. A company which gave its customers what it wanted (Yahoo) started to give its customers what its CEO wanted (entertainment) and went from being yesterday’s Google to today’s Yahoo.