Feed

what?
format for delivering regularly
changing content

uses
news (most popular) - cnn.com
latest photos from friend - flickr.com
latest change to wiki - wikipedia.com
latest changes to code - subversion
latest bugs - teamtrack
latest weather - weather.com
Anything which needs to publish latest items that can be
broken into discrete items

how does it work
Website publishes a link for its Feed
User subscribes to it, by adding the link to his Feed Reader
The Feed reader requests the latest items from the Feed
It displays the items which the user hasn't read yet
It refreshes the feed at fixed interval