Josh Peck

After making a chancy investment to open a temporary storefront at the Grove mall this Christmas season, online retailer Revolve Clothing clicked open what it calls its bible and did more than just pray for success.

For Revolve's five-person marketing team, the sacred text is an Excel spreadsheet listing nearly 100 consumers, most of them young women, who could make or break the bricks-and-mortar experiment.

High on the list was Chriselle Lim, 29, of Manhattan Beach. A committed Revolve fan, she immediately said yes when asked to help promote the storefront. Revolve paid for her Uber ride to the store on a rainy day in early December and gave her credit to buy a light-pink...