Cloud Computing (CloudC) is one of the most prominent recent trends in the digital communications sector and represents a paradigm shift within the ICT industry. The supply of popular applications, such as cloud storage and cloud video streaming, has caused a surge in the demand for CloudC services, which offer the advantages of low economic cost, high data transfer speeds, and improved mobility, security, scalability, and multi-tenancy. In this chapter, we investigate the circumstances under which this new CloudC infrastructure is likely to reduce energy use of our new digital lifestyle, or when it simply catalyses a rebound effect that could hamper ICT-related energy savings. We classify CloudC rebound effects as either direct or indirect rebound effects, and we discuss the differences and overlap between rebound effects, enabling effects, and transformational effects. An understanding of these differences is important for understanding energy use associated with CloudC.