This work analyses aspects of the citizens-state dialogue in the World Wide Web, considering the technical configuration of interactive resources in the Internet as well as the optimization of this process by designers. The study object is the usability and Information Architecture aspects of the IBGE portal. This portal is an emblematic example of the Brazilian e- Government communication challenges. This site disseminates large amount of statistical data - socioeconomic, ecological and geographical - that contributes to the formulation of state policies and social action, as well as helps in its dialogue with civil society. This thesis analyses the strongest and weakest points of the IBGE site Information Architecture and evaluates - from the usability point of view - its effectiveness in granting wide access to information to society as a whole. In the theoretical dimension, the work investigates possible connections among Information Architecture, Information Science and Organization Theory applied to the case study. Oral history interview techniques were applied in content inventory and context research. To study user behavior research, this thesis investigated information search, mental models and user tasks. Based on the identification of target audience groups, field usability tests were run with the participation of graduate and post-graduate students. Throughout this work, institutional change issues related to the e-Gov initiative in Brazil were discussed.