2. A computer-implemented method for subscribing to a calendar publication, the computer-implemented method comprising: providing the calendar publication, which includes a subset of calendar events from a source calendar database and qualified based on a set of criteria including one or more query conditions; defining, based on user input, one or more calendar subscription definitions including: (i) an identifier for the subscription; (ii) a locator or identifier to find and access the calendar publication, from a source calendar database, the subset excluding at least one calendar event in the source calendar database, wherein the calendar publication is uniquely identifiable and exists independently of any subscriber count thereto; and (iii) a transformation rule to map the calendar events from the calendar publication to one or more categories in a subscriber calendar; wherein the calendar publication is made available for subscription, without first requiring a publisher of the calendar publication to ascertain any subsequent subscriber to the calendar publication, wherein the calendar publication is platform-independent relative to at least one of: (i) a plurality of calendaring database platforms and (ii) a plurality of calendaring client platforms; activating a subscription agent for processing each calendar subscription definition by removing existing events in the subscriber calendar that belong to the one or more categories to which calendar events from the calendar publication may be mapped; transforming the calendar events according to the defined transformation rule in order to map the category of each event to the one or more subscriber categories for the calendar publication; and loading the transformed calendar events from the calendar publication into a calendar database, with the mapped category values, of a subscriber.
9. The computer-implemented method of claim 2 , where the transformation rule for mapping the calendar events to one or more specific categories in a calendar subscription definition maps all calendar events contained in the designated publication for that calendar subscription definition to a single specified category wherein the subscription agent performs the removal process for such a calendar subscription definition by removing all existing events in the subscriber calendar that belong to that specified one category for that calendar subscription definition before loading the calendar events from the defined publication of that calendar subscription definition.