The article begins by presenting a model for the structuring of customer data which can be used to demonstrate the value of data in different forms of aggregation. Since Customer Value plays a crucial role in this model the term is examined more closely. As part of a value-based customer relationship management critical parameters are customer benefits and customer profitability. Both perspectives are included in the term Customer Value. A segmentation approach is shown which integrates the key measures of customer relationship management: value generation from the customer perspective ("Value to the Customer") and value generation from the company's perspective ("Value of the Customer"). The practical application of the method is demonstrated with typical cases concerning both, B2B as well as B2C markets.