Idea

Users should be able to subscribe to events, and be able to choose which calendar to show the events in. F.x. imagine a user like 2-3 tv'series/shows, and the tv channel then offer a feed link to when theese shows a shown each week, then the user can subscribe to theese and easily in his/her calender see the schedule, without having to check a general tv schedule with a lot that doesnt interest them. Or it could be sport events, or similar.

In principle that can be done by the publisher offering a simple ICal feed, which then is the same as showing/importing some other users calender. So maybe the idea aint that great, unless ofcourse the api offers methods for the publisher to easily publish these ICal feeds (or publish to some certain calenders which then has the feeds). Some publisher will probably find it easier if they can call some function on a remote system with some input vars, then considering to make their own calendars and ical publishing. So basicly it needs that a user can easily add events and more with remote calls, which is actually already done. Then the trick mostly seem to make possible publishers aware of this feature.

In principle just the same as facebook and other social sites where u get updates from others, excep tthey dont show it in a calendar like its an event at a certain time.