This study aims to identify different styles of personal digital information categorization based on the mindscape of the categorizers. To collect data, a questionnaire, a diary study, and 2 semistructured interviews were conducted with each of 18 participants. Then a content analysis was used to analyze the data. Based on the analysis of the data, this study identified 3 different types of categorizers: (i) rigid categorizers, (ii) fuzzy categorizers, and (iii) flexible categorizers. This study provides a unique way to understand personal information categorization by showing how it reflects the mindscapes of the categorizers. In particular, this study explains why people organize their personal information differently and have different tendencies in developing and maintaining their organizational structures. The findings provide insights on different ways of categorizing personal information and deepen our knowledge of categorization, personal information management, and information behavior. In practice, understanding different types of personal digital information categorization can make contributions to the development of systems, tools, and applications that support effective personal digital information categorization.