The T3 Innovation Network organized Work Group 4 to explore the most important stakeholder use cases relevant to new architectures and uses of linked individual-level data consistent with relevant T3 guiding principles. This work group report first summarizes the most important stakeholder use cases for the application of Web 3.0 technologies. Next, the report summarizes major issues and technological challenges that cross-cut these use cases; enumerates potential pilot project ideas that have emerged through the group’s discussion; and mentions potential ethical considerations.