In today's information society people have to manage an overload of information adequately. Being able to search, find, evaluate, select, process, organize and present information in order to acquire new knowledge is an important skill. This skill is defined as information-problem solving (IPS). However, research shows that many students are not able to solve information-based problems successfully, and that they have especially problems with the ability to organize found information. Organizing information in a proper way is not easy. Because people are used a hierarchical system, it seems natural to categorize information in classes and subclasses. Although hierarchical classification systems are a good way of bringing order in a collection of physical objects, with the use of virtual information objects it becomes possible to organize the information with labels or 'tags'. Consequently, information can be attributed to different classes. However, organizing information in a proper way is not a skill which is learned easily. Guidance and/or instruction is therefore needed. The poster presents a theoretical overview.