A key challenge for companies in the e-business era is to manage customer relationships as an asset. In today?s global economy this task is getting, at the same time, more difficult and more important. In order to retain the potentially good customers and to improve their buying attitude this paper proposes a hierarchical fuzzy classification of online customers. A fuzzy classification, which is a combination of relational databases and fuzzy logic, allows customers to be classified in several classes at the same time and can therefore precisely determine the customers? value for an enterprise. This approach allows companies to improve the customer equity, to launch loyalty programs, to automate mass customization and to refine marketing campaigns in order to maximize the customers? value and, this way, the companies? profit.