Inhaltsangabe: Abstract: The worldwide economy is currently in a state of upheaval. For decades the traditional marketplace was the common way to buy goods, services and to do business. People set up shops and met in conference rooms to negotiate big business deals. However, since the middle of the 90's the business world has been undergoing a tremendous change. While the basic rules for doing business have not altered, conditions and terms have changed significantly. The emergence of the Internet was the main catalyst for this drastic change in the business world. At first the Internet was considered to be merely another medium with which people had to deal with. It was regarded as a concomitant which did not necessarily have to be used in companies. But the possibilities the Internet offered were and are tremendous. Both private people and companies discovered the opportunities harboured by the Internet. Firms quickly realised that the Internet can and must be a medium which was worth taking a closer look at. The same applied for individuals. However, the very purpose of its work, which is communication between private people over the Internet, can be overlooked and neglected in this context. The first part of the present thesis focuses on the Internet and how companies and individuals use the digital environment to do business. The objective of firms is mainly to do business, either with other firms or with private people. The Internet is considered to be a medium and an interface both parties have to use. With the help of the Internet, companies are expected to increase their efficiency and reduce transaction costs. The unique characteristics of the Internet such as its omnipresence promise both parties an increase in their business activities. Furthermore, the Internet has to be perceived as a great, parallel world to the traditional, existing one. Of course, companies can exclusively exist and compete on the Internet. But what they must not neglect is