I'd like to publish a list of events in the iCal format. My question is - if I have a public ICS file that I add/update events on, will clients like google reader and outlook receive those updates automatically? i.e. - does it behave like an RSS feed that gets periodically pinged for changes or is it a one time import?
Thanks
It depends how the client is configured. For instance, in Korganizer I often do one-time imports (e.g. departure times when I book a flight). But I have other ICS files (e.g. organizational calendars) where I set it do pinging.
One time import. See Wikipedia, it basically represents a mechanism for sending one or more appointments.
If the iCal is published and updated, and your client can be set to periodically refresh, you may get the effect of a subscription to an RSS, but really it is a series of imports.