Neiman Marcus is introducing a contest designed to reel in its fussiest shoppers, called the "What's Your Passion for Fashion? Challenge." In the first round, consumers pull together looks from its fall offerings, and write a description of why their selections are perfect for fall. Contestants can post their results on Facebook and Twitter, and the Neiman Marcus site assigns a viral score to each entry. At the end of next month, the Dallas-based retailer will select 42 finalists to move on to a second round, competing for a $5,000 gift card.