This paper is to clarify the current status of smart systems and discuss the progressive formation of the privacy protection ecosystem for smart cities in Japan. The authors surveyed representative smart city projects, promotion groups, and several privacy protection platforms as case studies. As a result, the authors obtained the following three findings. First, Smart Grids and Smart Intelligent Transport Systems have been progressing steadily. Second, several proof of concept in privacy protection platforms have started recently. Third, these privacy protection platforms are classified into two types: a centralized model and a distributed model. Therefore, it is important for the progressive formation of privacy protection platforms in smart cities not only to integrate the centralized model and the distributed model with a hybrid model based on the structure of Multi-sided Markets and Freemium business model, but also to examine a trust framework of privacy property to formulate its secured services at a low price, before full-scale smart systems come into use.

This paper examines a Personal Information Trust Service as a conceptual model of a Personal Data Service to unlock personal data from collection to use without privacy invasion. Personal Data Service is a service to let an individual store, manage, and deploy their key personal data in a highly secure and structured way. First, the authors explore an accounting cloud service with two-sided markets structure and freemium business model and discuss success factors of its diffusion. Second, they illustrate the duality of structure situated between the business model of the accounting cloud service and Personal Data Service. Third, they examine a conceptual model of Personal Information Trust Service as one of Personal Data Service. At last, the authors discuss strategies for diffusion of the conceptual model and examine introduction to a smart city in Japan.

The purpose of this study is to clarify the best practice of an accounting cloud service in Japan which has two-sided markets and freemium structure and how to formulate its service. The authors studied one specific accounting cloud service, as a case study. As results, the authors obtained the following three findings. First, the best accounting cloud service adopted Open & Close strategy. The Company specializes in accounting operations area and make open connections with other cloud services in non-accounting operations area. Second, the best accounting cloud service has a specific service formation along its market strategy. Third, the best accounting cloud service has an effective boarding strategy of its users' group onto its cloud service platform. Therefore, cloud service providers not only adopt Open & Close strategy, but also build up the coherent market strategy to formulate self-reinforcing mechanism before building up their business ecosystem in the two-sided markets and freemium structure.

The purpose of this article is to clarify an organizational continuum of a technological platform development in a Japanese accounting cloud service. The authors continuously have been studying an accounting cloud service, which adopts two-sided markets structure and freemium business model. As the results, the authors obtain three findings. First, the Japanese accounting cloud service, which runs its business with regional banks in retail banking, has been exploiting its platform into partners' customers. Second, it has been building up from a supply-chain platform to an industrial platform in four years since its entrepreneurship. Third, it has been transforming its cloud-to-cloud service connections from weak-tied interfaces to its own strong-tied interfaces. Therefore, starting-up cloud service providers should not only utilize weak-ties to establish a structural hole, but also should develop its own strong-ties and indirect ties to tighten upon its two-sided markets structure in its cloud ecosystem.

The purpose of this study is to clarify the best practice of marketing strategy in Japanese accounting cloud services. The authors examine platform development and ecosystem formation of an accounting cloud service in the second stage. As the results, the authors obtain three findings. First, the best accounting cloud service has been driving a spiral model of marketing strategy consistently. Second, customer groups of the cloud service, which are connected by chain composition with path dependence, constitute multiplex markets structure. Associated service groups, which are also connected chain composition, constitute multi-dimensions service structure. Third, the service provider has started new Open & Close strategy that involves formulating closure of network structure of associated services. These strategies realized its sustainable growth. Therefore, cloud service providers not only adopt Open & Close strategy, but also build up a spiral model of marketing strategy to formulate two chain compositions with path dependence for customer groups and associated service groups.