Knowledge Cities fall under a new area of academic research entitled Knowledge-Based Development (KBD), which brings together research in urban development and urban studies and planning with knowledge management and intellectual capital. The purpose of this paper is to highlight the importance of social computing and a promising role it could play in the implementation of Web-based Knowledge City Portal. A collection of academic and practitioner papers/articles related to social computing, web portal, knowledge city and related areas are analyzed and critiqued. Four critical dimensions namely Accessibility, Affordability, Usability, and Functionality are identified and analyzed to form a conceptual implementation model for a Web-based Knowledge City Portal.