The chapter deals with customer relationship management in traditional metal business. It introduces a new concept for handling customer interfaces. Based on the experience gained from this application, the following conclusions may be drawn. Integration of different components of profitability improvement is one of the main potentials of Key Customer Management (KCM). Long-term continuous development process is more important than a huge number of simultaneous and/or successive development projects. The business process and the contents of information systems—especially e-Commerce systems—is more important than the technical solution.