A startup, David Heinemeier Hansson argues, will never have the resources to outspend a Google or a Microsoft in promoting itself. Instead, his own company 37signals tries to out-teach. “We’re trying to build an audience; we’re not just trying to have customers.” Through blogs, lectures, seminars and other teachable moments, he explains that 37signals has created a following of the company that may not use the product today. But at some point, these people will either buy our product or recommend it to someone who will. In the end, all sustainable businesses are built by word of mouth.