Looking at the ongoing evolution in electronic commerce there are more and more business models becoming significant. E-shops, e-auctions or etendering are not the only possibilities for a company to be active in electronic commerce. This article presents many relevant business models and systematically classifies them. Mainly the classification is based on the type of business subjects like suppliers, customers and mediators and their active or passive role as initiators and carrier of a business model. Another basis for the classification is the breakdown of the concept of electronic commerce and an explicit modeling. This allows to build up a taxonomy using multiple criteria and the presentation and subsumption of individual business models. The taxonomy can be used to analyze and enhance existing systems and business models as well as to develop new internet strategies for companies. An example of the implementation of the business model e-portal concludes the article.