Assigning rights to calendars and events is the key to sharing. Each calendar has a set of rights which are set by the calendar's owner, and events on that calendar can inherit rights from the containing calendar, or they can have their own settings.

Viewing

Viewing rights allow people to view events. You can think of it as a read-only mode. You can let everyone view, or share it with a few friends of your choosing.

Posting

By granting posting rights, you allow people to create events on your calendar. This also means you grant them viewing rights. You can open posting rights to everyone or limit it to a select few.

Update

The update privilege gives people the ability to edit events on your calendar. This also gives them posting rights, which in turn gives them viewing rights. You can also delete events with update rights. Again, who gets the rights is up to you.