I like Mark Leslie's HBR article about The Sales Learning Curve:

When a company launches a new product, the temptation is to immediately ramp up sales force capacity to acquire customers as quickly as possible. Yet in our 25 years of experience with start-ups and new-product introductions, we’ve found that hiring a full sales force too fast just leads the company to burn through cash and fail to meet revenue expectations. Before it can sell the product efficiently, the entire organization needs to learn how customers will acquire and use it, a process we call the sales learning curve.