1. Introduction
Throughout the last years interoperability has been in the focus of e-government practice and research. The term itself refers primarily to a technical challenge, i.e. the technical capability for e-Government inter operation. “Interoperation in E-Government occurs whenever independent or heterogeneous information systems or their components controlled by different jurisdictions/administrations or by external partners smoothly and effectively work together in a predefined and agreed upon fashion.” ([19], p. 900)