Mobile radio technologies have been subject to speculations in recent years. The initial euphoria about opportunities and market potentials of mobile services and applications has mainly been caused by growth expectations in the field of non-voice-orientated services. For the year 2003 optimistic analysis of the market development already predicted an expected total volume for the European sales of more than 23 billion Euros (Müller-Verse, 1999). But such expectations appear to be hardly achievable. In 2003 the German Ministry of Labour and Economics merely show a sales volume of US$71 million for Europe. Based on this number, an increase up to US$119 million until 2007 is predicted (Graumann/Köhne, 2003).