Informal note taking is an essential activity in Personal Information Management (PIM). Most mobile devices support this via a suite of applications, employing both highly structured (e.g., calendar, task list, contacts) and loosely structured (e.g., memos) data formats. Contextual interviews and artifact inspections with expert PIM-on-PDA (Personal Digital Assistant) users explored task-toapplication mapping. Structured tools were routinely avoided for informal note taking in favor of unstructured ones, even though this made managing the information more difficult. Improved support lies somewhere in between, suggesting the design of an integrated architecture, which links data across all PIM tools and provides a persistent, universal organizational system.