On Friday 27th November 2015, REI did a remarkable thing. It closed the doors of all 143 of its retail stores, its headquarters and its two distribution centres. On this day, REI paid every one of its 12,000 employees to #OptOutside - to enjoy the great outdoors with friends and family - and invited all its customers and the entire American nation to join them. The most astonishing fact about the #OptOutside store closure was that it took place on Black Friday: the biggest shopping day of the year. Turning its back on millions of dollars' worth of sales, REI went ... against a cardinal rule of traditional business. Instead of cashing in on a one-day opportunity for inflated profits, it chose to act in a way that would best support its purpose - that of 'inspiring, educating and outfitting its members and the community for a lifetime of outdoor adventure and stewardship'. Here's how Jerry Stritzke, REI's president and CEO, explained the decision: "As a member-owned co-op, our definition of success goes beyond money. We think that Black Friday has gotten out of hand and so we are choosing to invest in helping people get outside with loved ones this holiday season, over spending it in the aisles." It was a risk for sure, but the payoff has been sensational. More than 1.4 million people responded to REI's invitation to #OptOutside, and 175 organisations - companies as well as non-profits - joined the movement. It was a response that showed not just tremendous levels of engagement, but engagement of the highest order.