The core issue for this study concerns less the social than the political consequences of the rise of knowledge societies; in particular, the capacity of the Internet for strengthening democratic participation and civic engagement linking citizens and government. To consider these issues, Part I summarizes debates about the impact of the Internet on the public sphere. The main influence of this development, as it is theorized in a market model, will be determined by the “supply” and “demand” for electronic information and communications about government and politics. Demand, in turn, is assumed to be heavily dependent upon the social characteristics of Internet users and their prior political orientations. Given this understanding, the study predicts that the primary impact of knowledge societies in democratic societies will be upon facilitating cause-oriented and civic forms of political activism, thereby strengthening social movements and interest groups, more than upon conventional channels of political participation exemplified by voting, parties, and election campaigning. Part II summarizes the sources of survey data and the key measures of political activism used in this study, drawing upon the 19-nation European Social Survey, 2002. Part III examines the evidence for the relationship between use of the Internet and indicators of civic engagement. The conclusion in Part IV summarizes the results and considers the broader implications for governance and democracy.