Really Simple Syndication (RSS) is a lightweight
XML format designed for sharing headlines and other Web content.
Think of it as a distributable "What's New" for your site.
But it's not just for news. Pretty much anything that can be broken
down into discrete items can be syndicated via RSS: the "recent
changes" page of a wiki, a changelog of CVS checkins, even
the revision history of a book. Once information about each item
is in RSS format, an RSS-aware program can check the feed for changes
and react to the changes in an appropriate way. Attention, your
browser may not support RSS/xml.
RSS and Mac OS X: