The concept of versioning as used herein has nothing in common with the concept as used by software developers. In our research, versioning refers to the marketing of a GI service in different quality versions for different prices in order to satisfy different customers with different willingness to pay (Shapiro and Varian 1998 and 1999, Varian 2000). But every user who requests the same GI service quality pays the same price. This approach is also referred to as vertical differentiation or price- quality discrimination. In this context, we take up two definitions to describe the nature of the quality.
