One of the key goals of Network Functions Virtualization (NFV) is achieving energy efficiency through workload consolidation. A good example for maximizing energy savings is the Virtualization of Content Delivery Networks (vCDNs) NFV use case where the video streaming workloads exhibit significant difference between prime-time and non-prime-time usage of the infrastructure. This paper examines the practical challenges in maximizing energy efficiency for vCDN workloads. This paper proposes an open NFV architectural framework for conveying content virality information from Cloud applications such as YouTube, Twitter and mechanisms for leveraging it to maximize the energy efficiency for vCDN workloads. This paper also proposes a more general architecture for any Cloud/NFV application that may experience virality.