Digitalization challenges existing organizations and industries. The associated advancement changes the way organizations and their customers interact. This has increasingly fostered the emergence of platforms to facilitate such interaction. Online platforms are software or hardware infrastructures that serve as a foundation and facilitate the interaction between multiple parties (e.g., between organizations and users). Organizations create platforms as part of a larger ecosystem. One major challenge concerns the design of platform-based ecosystems so all participants benefit from their participation. The management of associated relationships with other ecosystem participants is consequently a key challenge and demands according foresight. Platform-based ecosystems are subject to research in the field of information systems. Thus, scientific literature addresses many corresponding research questions and provides valuable insights for both research and practice. However, organizations face numerous challenges when engaging in ecosystems. Such challenges are, e.g., to develop new ecosystems, to incentivize participants to participate in the ecosystem, to cooperate with other participants, and to monitor the ecosystem. In this respect, this doctoral thesis provides a brief overview of platform-based ecosystems and the respective participants therein. Further, the thesis addresses four key challenges in the context of platform-based ecosystems, and proposes novel approaches in order to overcome the challenges. The basis for the novel approaches stems from five research papers. The first and second research paper address the challenge of determining design options when developing new ecosystems via blockchain-enabled initial coin offerings. The papers feature a taxonomy and derive predominant archetypes by drawing on real-world cases. The third research paper addresses the challenge of incentivizing users to participate in platform-based ecosystems. The paper proposes an approach to model financial incentives concerning platform adoption. The fourth research paper proposes an approach to analyze organizational cooperation patterns for the purpose of innovation integration. The developed approach incorporates taxonomy development and enables organizations to determine cooperation characteristics to align the cooperation decision with the cooperation objectives. The fifth research paper addresses the challenge of monitoring customer sentiment on online platforms. The proposed design science research artefact includes a detector of negative sentiment such that organizations are able to identify when a negative sentiment develops, and intervene before users spread the sentiment, e.g., through comments. Each research paper answers a stand-alone research question in the realm of platform-based ecosystems and derives a theoretically founded and separately evaluated research artefact. The artefacts draw on underlying, well-established research methods that allow answering the respective problem statements. Since the problem statements are motived in a practical context, this thesis bridges the gap between a practically oriented problem and a theoretically founded solution. As a result, the derived insights contain a contribution for both, research in the field of Information Systems and practice audience, and encourage the engagement of both domains
