To facilitate the search process of users on an electronic commerce website we developed a new Graphical Shopping Interface (GSI). This interface presents groups of recommended products in a map based on product characteristics. In this map, products that are similar to each other are located close to each other, while dissimilar products are located far apart. The recommendation approach used in the GSI is works as follows. First, eight products are randomly selected and shown in a map to the user. When the user chooses the product she likes most, we recommend seven new products more similar to this product and show these in a new map together with the chosen product. This process repeats itself leading to evermore similar products. We evaluated the GSI in a usability study created in GlobalPark. In this study, the GSI Java applet was integrated into the survey environment, so that no switching between the GSI and the survey was necessary. The applet accessed a database outside Global Park to store information gathered in the GSI. In total, we gave the respondents four tasks, which they had to perform either with the new GSI or a traditional interface. To avoid order effects, both order and assignment of tasks to an interface was randomized. In this presentation, we discuss the setup of the present usability study and show how the implementation was done in the Global Park environment.