In this paper I discuss the digital city as a comprehensive, web-based representation, or reproduction, of several aspects or functions of a specific real city, open to nonexperts. Much more than a technical and practical issue, the digital city has dimensions that are social, cultural, political, ideological, and of course also theoretical. I explore these broader conceptual underpinnings of the digital city idea. More specifically: where do urban ideologies, urban structures and functions, and digital urban representations meet? How may the digital city relate to the real city? On the basis of what choices might the digital city be constructed? What might the digital city mean to people? To be answered, these highly involved and interrelated questions require a coherent conceptual framework. By considering an overview of digital-city realizations, issues, and critiques, I adumbrate a theory of the digital city, seen as lying at the intersection of three domains: a physical urban area, the communities of people associated with that area, and the possibilities and constraints (technological, but also socioeconomic and ideological) of the evolving information society. A rough sketch is all that can be offered at this point because proper theories of the digital city cannot be developed independently of comprehensive theories of the real 21st-century city. I close with a brief discussion of what these ideas might imply for digital-city designers.