To make a grass roots or personal connection. As a company gets larger, often times they lose the reputation of caring about their community, individual customer or employee. Local stories about local people carry great weight within local communities. A company that captures stories about its everyday heros demonstrates that it hasn't lost concern for the individual. The classic case study has been used by companies to sell products or services for decades.
Stories are simply a great, timeless way to illustrate benefits for prospects and customers.
To facilitate change. Because businesses must change more rapidly than ever before, stories are more critical than ever. They help employees see themselves creating and delivering new products. They help customers see themselves using new products and services or interacting with an organization in an unfamiliar way. To solidify an identity.