You can create an ical export menu item where users can select categories and years they are interested in.
For notifications - these only go to the event administrator (and category admin if you configure this option).
If you want email notifications to go to your registered users then you need the Events Notifications addon available to silver members of the Jevents club. This can be configured to notify different groups of users when events are created, changed or unpublished. Also users can select categories they are interested in via an associated module to get notifications of new events by category.