Taxonomies are utilized by retailers to facilitate customers navigating through a marketplace with the help of hierarchically structured concepts. However, when entering the marketplace, each customer is shown the identical taxonomy regardless their individual requirements, which leads to two problems. Firstly, as preferences are not considered, the customers are distracted by reading the labels of low required concepts that are initially siblings of high required concepts. Secondly, as the limitations of different devices and channels are not considered, customers using devices with smaller displays, or customers using printed catalogs, are having difficulties in finding the desired concepts. To modify taxonomies according to customers’ specific requirements, this Ph.D. thesis is presented.