 Smart technology is often associated with automation, enabled communication, and service integration. However, there is a gap between these technologies and their actual intelligence. This has led to a debate between works focusing on automation and mechatronic design versus those pursuing a conceptual approach based on fulfilling determinant objectives. Another perspective relating to smartness is through deep learning methodologies. This paper provides an overview of recent works related to energy usage for smart cities and the smart grid, as well as the technological foundations that support the smart concept. It also discusses how enabling technologies and current trends in energy consumption are shaping the ongoing efforts toward a more sustainable future. The paper concludes with a new definition of smartness, which is distinct from the typical misunderstanding of technological nesting or mere usage of advanced digital technologies. Instead, smartness is defined by the integrative objectives the application pursues, the objectives set by its users, and the attained results in terms of public benefit. This article was authored by Ignacio Lenas Caballero, Luis Ibarra, Angel Pena Quintel, and others. We are article.tv, links in the description below.