A conceptual framework for digital economy is proposed, consisting of six elements: the Internet standard, open and universal communication protocol; the electronic interconnection of people, things, institutions and countries; the separation between the economics of things and the economics of information; the overcoming of the trade-off between reach and richness in information economics; the dematerialization of the economy; the shift from ownership to access economy. The theoretical background refers to the pioneering works of Evans and Wurster, Shapiro and Varian, and especially to the contribution of Valdani, an Italian scholar who explained the ICT-driven evolution of the economic system according to the interaction of the first four above-cited elements. The model adds two more building blocks, reviews the framework according to technological innovation and finally lays the six elements in a hierarchical way, to show cause-effect relations.