21. The computer-implemented method of claim 19 , wherein each calendar publication definition further comprises one or more transformation rules for transforming the data contained in fields of the qualified calendar events from the calendar database, wherein processing each calendar publication definition by the publication agent further comprises applying the respective one or more transformation rules to the qualified calendar events such that field values of the qualified calendar events are transformed before inclusion in the calendar publication; wherein the calendar publication definition further comprises one or more transformation criteria for determining whether or not the transformation rules should be applied to a qualified calendar event from the calendar database, wherein the publication agent, for each calendar publication definition, evaluates the one or more transformation criteria for each qualified calendar event before conditionally applying the relative transformation rules to the qualified calendar events that meet the required transformation criteria.
19. The computer-implemented method of claim 16 , wherein the publisher is permitted to define and apply qualifying criteria in order to exclude at least a first calendar entry, while the one or more subscribers are also permitted to define and apply respective qualifying criteria independent of and in addition to the qualifying criteria applied by the publisher and in order to exclude at least a second calendar entry, thereby facilitating customization of display of the calendar publication both from a publisher perspective and from a subscriber perspective; wherein the calendar publication supports platform-independent access control in terms of limiting access to one or more calendar events and without using any access control functionality specific to any of the calendaring databases, wherein the one or more subscribers are permitted to customize display of the calendar publication using rule-based subscriber preferences that are automatically re-applied upon synchronization.