Organization Default Settings apply to any new events that are created (except the Colors and Tracking settings, which apply to all new and existing events). It is therefore advisable to customize these in the beginning so that they can apply to any new events you create.
Note: You can use the Revert button to revert Organization Default Settings back to the System Default Settings. If you click Revert, any custom changes you made to your Organization Default Settings will be lost.
Event Settings are unique to each Event. When a new Event is created, a copy of the Organization Default Settings becomes part of the new Event. When an Event is copied, the Event Settings are copied from the Event being copied. Modifying Event Settings will NOT affect settings with any other event or the Organization Default Settings.
Note: Clicking the Revert button on Event Settings for any Event will revert the selected Event’s Settings to the Organization Default Settings.