A better short summary: because 37signals is B2B, and because they sell productivity tools, companies are more likely to view their 37signals product purchase a

A better short summary: because 37signals is B2B, and because they sell productivity tools, companies are more likely to view their 37signals product purchase as an investment. What this means is that people believe the purchase will help their company's productivity (and therefore increase revenue). This is the real reason behind the high 'willingness to pay' that we see in 37signals's business model.