In this paper, we introduce an approach to identifying and ranking cities in the current Information Age. Mindful of Manuel Castells' call for a "new spatial logic," we argue that the informational "flow" characteristics of contemporary inter-city connections has to be taken into account when measuring the (relative) "importance" of cities. While recent information-based studies on urban networks are valuable additions to the global urban systems literature, we would argue that there remains a lack of up-to-date and updatable studies of information flows that acknowledge that these flows are intangible and not simply embodied in people (in the case of airline network analysis) or places (in the case of studies that focus on the physical, enabling infrastructure of electronic communications). In order to understand more about cities and their relative positions in the Information World, we should study not only tangible informational infrastructures and their associated material flows between places, but also the cyberspaces of cities in relation to digital information. To illustrate our approach, we introduce and argue that Web search engine databases comprise appropriate datasets for examining the growing importance of knowledge as a raison d'être for a city's economic ranking on national, regional, and global scales. Based on a quantitative and qualitative hyperlink analysis utilizing the leading and de facto standard Web search engine Google, we derive informational rankings of the world's 100 largest cities in respect of two prominent current issues global in scope: the global financial crisis, and global climate change. Results include: that traditional, developed Western cities are most prominent in terms of the environmental measures while, in terms of the financial criteria, "new" Asian financial centers are ranked more highly. The paper concludes by outlining an agenda for further work on Web-based informational city rankings.-3 -