on of the "whole product" and share of services (Moore 1995, p.155) along with the technology adoption life cycle (Moore 1995, p. 14) From Moore's viewpoint, gaining critical mass is needed for crossing a chasm between Innovators and Early Majority. The critical mass is usually obtained with the help of partners implementing complementary services for the technology product of the primary innovator company. The concept of the whole product can easily be explained. In a software market, the whole product contains typically a core software product provided by a software product company and complementary integration services provided by, for exam- ple, an IT consulting company. For example, in the early phases of ERP technology evolution the product licenses of SAP accounted for about 20% of the sales price of a customer delivery (Hoch 1999) while services of IBM, Accenture and other IT integrators accounted for about 80% of the delivery. The price erodes along with the reducing volume of services, until in the late phases of the life-cycle the product vendors try to increase their sales volume by increasing service revenues. This development is well in line with the view of Moore presented in Fig. 2. Along the same lines, the life-cycle and growth models proposed by Greiner (1972), Churchill and Lewis (1983), Scott and Bruce (1987), Nambisan (2002), Kazanjian (1988), and McHugh (1999) observe the life cycle of companies in general or high-technology companies, from the perspective of the software com- pany rather than from the perspective of the status of some vertical market. However, Greiner (1972) states that the growth of a company is often related to the market environment and stage of the industry. From our perspective this is essential, since the development of software businesses servicing specific vertical markets depends both on the status of the primary software industry and the vertical market. Next we shall look at the industry evolution models. Theories Related to Vertical Software Industry Evolution 