Cloud computing enables an entire ecosystem of developing, composing, and providing IT services. An emerging class of cloud-based software architectures, serverless, focuses on providing software architects the ability to execute arbitrary functions with small overhead in server management, as Function-as-a-service (FaaS). However useful, serverless and FaaS suffer from a community problem that faces every emerging technology, which has indeed also hampered cloud computing a decade ago: lack of clear terminology, and scattered vision about the field. In this work, we address this community problem. We clarify the term serverless, by reducing it to cloud functions as programming units, and a model of executing simple and complex (e.g., workflows of) functions with operations managed primarily by the cloud provider. We propose a research vision, where 4 key directions (perspectives) present 17 technical opportunities and challenges.