To achieve a critical mass, it is crucial to distinguish clearly between three types of notes: 1. Fleeting notes, which are only reminders of information, can be written in any kind of way and will end up in the trash within a day or two. 2. Permanent notes, which will never be thrown away and contain the necessary information in a permanently understandable way. They are always stored in the same way in the same place, either as literature notes in the reference system or written as if for print, in the slip-box. 3. Project notes, which are only relevant to one particular project. They are kept within a project-specific folder and can be discarded or archived after the project is finished. Only if the notes of these three categories are kept separated will it be possible to build a critical mass of ideas within the slip-box.