The relevance of virtual and augmented reality as enabling technologies of the metaverse is increasing. Despite their importance for the metaverse, both virtual and augmented reality are not yet widely used. Besides technical limitations, a lack of effective use could be a reason for this. In the field of Information Systems, effective use is understood as the successful realization of a technology's potentials for action, or so-called affordances. This cumulative dissertation examined how the effective use of virtual and augmented reality can be promoted from a technical and socio-behavioral affordance perspective. From a technical affordance perspective, it was investigated how virtual and augmented reality systems should be designed to enable their effective use in the contexts of higher education and emergency management. The results show that effective use can be fostered by implementing design elements that promote the perception of the unique affordances of virtual and augmented reality compared with existing systems. From a socio-behavioral perspective, it was examined what user behavior constitutes the effective use of social (virtual reality) applications in which users pursue shared versus different goals on the same platform. The findings reveal that effective use behavior involves not only the successful realization of affordances, but also dealing with constraints emerging from technical limitations and interactions with other users pursuing different goals. The dissertation contributes prescriptive knowledge in the form of design principles and a better understanding of the user behavior that constitutes the effective use of virtual and augmented reality to Information Systems research.