Aiming to receive more feedback than customers provide on the five items mailed in each box, a Stitch Fix employee designed Style Shuffle, which allows customers to rate a set of clothing images each day. “A sort of Tinder for clothes, it became available on Stitch Fix’s iOS app in March and has proven to be stickily addictive: It not only trains the company’s algorithm to understand holistically a client’s personal style, but it also draws customers back to the app and interests them in Stitch Fix’s inventory,” according to Fast Company.