There's a critical common thread that runs through the four Web businesses profiled here -- a strong customer-centric focus. While an airline, a makeup company, a car company and a nonprofit organization have inherently different business models, the websites for Southwest Airlines Co., Ford Motor Co. employees, American Cancer Society Inc. and Mary Kay Inc. succeed because they recognize and deliver what their customers need.

Whether adding comprehensive travel services, giving intranet access to users worldwide, building Web content around users' experience or providing sales agents with individual webpages, these Web Business 50 winners each developed their sites with a clear customer focus.