KOrganizer is a several things. It is a calendar. It is a program to
keep track of your appointments. It is a prioritized todo list. It
coordinates scheduling between different people or groups. In short,
it is a program which tries to help you keep your life organized,
hence the simple, yet appropriate name. You may have encountered
similar programs for both UNIX and Windows such as plan, Netscape
Calendar, Microsoft Outlook, and Ecco Pro. All of these programs fall
under the same general category of "PIM," or Personal Information
Manager, and they all more or less try to do the same things, though
often with different angles of approach.

KOrganizer is the first free PIM for Unix which implements the
vCalendar protocol for personal data interchange. This
vendor-independent, open standard allows different programs and
devices to share/synchronize appointment and calendar information
without proprietary standards. The data is stored in ASCII and is
easily human-readable. While some Windows programs have implemented a
limited import/export ability for their native formats to vCalendar,
KOrganizer's native file format on disk is vCalendar, so it bypasses
this middle-step entirely. It also allows you to easily access your
data without the program itself, in the spirit of other UNIX programs.