By allowing customers to return Macy's and Kohl's merchandize in their stores, Nordstrom is capturing an important metric that most retailers ignore -- customer demand. In other words, what are customers buying (and what they are returning and why). Assortment planning is a huge problem for all brick and mortar players especially in the world where prospective customers will pull out their phones at the slightest sign of not finding what they came to look for. Nordstrom may have found a creative way to solve it.