This paper develops a new framework for explaining the dynamic aspects of business models in value webs. As companies move from research to roll-out and maturity three forces cause changes in business models. The technological forces are most important in the first phase, regulation in the second phase, and markets in the third. The forces cause change through influence on the technology, services, finances, and organizational network of the firm. As a result, partners in value webs will differ across these phases. A case study of NTT DoCoMo?s i-mode illustrates the framework.