RSS or Real Simple Syndicate is an XML formated file that is generally used to automatically publish new content out to subscribers. This will be either the entire story or just a summary of the just published information. Many if not most blogs and web pages offer an RSS feed, as they are commonly called, so that readers can use RSS Readers (online or applications) to view the latest news.
The idea is that the subscribers, once interested in what they read in the RSS headline, will click on the link and go to the host site. Besides a publishing tool, it also has a marketing value.
For more information on RSS and the various versions and technical specs, see:
http://en.wikipedia.org/wiki/RSS_(file_format)http://en.wikipedia.org/wiki/RSS_(file_format)