He was in web design. He got laid off. His employer offered him another job, but he knew: this was his chance to build his own thing.

Today if you run a small business or you're into marketing, you've probably heard of MailChimp. For everyone else, it's the way a lot of people reach their customers' email inboxes. Newsletters, offers for special sales, you name it – MailChimp is in the tricky game of helping companies reach the people who actually want to be reached.

Today, Ben Chestnut's team has more than 14 million users, and had more than $400 million in sales last year. Ben himself? An introvert. A soft-spoken guy who has perfected the art of capitalizing on the wrong answer and getting to the right one.