This paper addresses the dynamic nature of business model design in the online services business. It particularly focuses on revenue models as a critical driver for mobilizing the dynamics of business models in high-velocity market environments. It argues that a dynamic revenue model design should be a fundamental strategic practice especially for online services that face significant market and technological uncertainties. To discuss implications of dynamic revenue model design in real business contexts, we examine two Japanese online service businesses: Yahoo! JAPAN and GREE. We found that the framework of dynamic revenue model design offers both researchers and practitioners ean adaptable business perspective on turbulent online service businesses.