Application design driven by user needs is an increasing trend: such applications may not be anticipatable using traditional requirement and build approaches. Mashup refers to an integrated application programming interface (API) that combines data from different data destination or third party sources for Web services. This Web service provides a combined API that is technologically valid and compatible with other Web applications. In recent years, Web mashups have been tested for solving many issues in existing Web applications, such as e-science. In this paper, we analyzed a real service problem in a current virtual organization to show current limitations of using a distributed architecture, and to describe a Web service orientated architecture using the mashup concept. We provide a schematic solution for a paradigmatic user application problem, illustrated by a specific map usage need based on geographical information system data. Specifically, our illustrative application is finding the closest hotel within walking range of a meeting venue. Based on the case issues, we outline a generic architecture that offers a dynamic solution for Web portals providing services for dynamic user needs.