Managing innovation in rapidly moving environments, such as Internet-based services, is a major challenge in theory and in practice. Most of the existing literature focuses on the development process as the main area in which innovation takes place. However, in environments where the pace of change of technology and market needs is extremely high, managing service innovations means not only being able to design a good service but also, more importantly, continuously redesigning and adapting the service in order to deal with frequent exogenous changes and opportunities. A high number of innovations therefore must be introduced throughout the entire life cycle of a service. This capability of introducing incremental and radical innovations during the service life cycle (i.e., to adapt a service to contextual changes and opportunities after it has been first released onto the market) at low costs and in the shortest possible time is what is defined here as service life-cycle flexibility. This process of service adaptation and upgrading implies significant challenges that can be traced back to when a service is first conceived and designed. In fact, many decisions made during the first design process (i.e., the choice of a given database environment) involve a low reversibility rate and may reduce the possibility of taking advantage of future unpredictable opportunities, creating what is called inertia toward innovation. In other words, service life-cycle flexibility largely depends on how a service has been first designed. This article analyzes two in-depth case studies of Italian online newspapers and identifies five possible inertia factors that may influence service life-cycle flexibility, namely (1) technological inertia; (2) internal organizational inertia; (3) external organizational inertia; (4) customer inertia toward changes in the service package; and (5) customer inertia toward changes in the service interaction design. These inertia factors are traced back to the service development process in order to suggest design practices that may increase the service life-cycle flexibility.