RSS stands for Really Simple Syndication, and is a web format for delivering regularly updated web content. Many news sites, blogs and other online publishers distribute their content as an RSS feed for readers to frequent their site. The "feeds" contain either a summary of content from the associated web site or full text

RSS allows you to stay informed by regularly retrieving the latest content from the sites you are subscribed to, and stores it all in one place until you are ready to read it. "RSS readers" display the subscribed content in a way that makes it easy to scan the headlines easily and decide which articles or blog postings you would like to read rather than searching through the entire site.

You save time by not visiting each site individually, and maintain your privacy by not having to join each site’s email newsletter. If you don’t want to subscribe to an RSS feed anymore, you can simply delete the feed. RSS eliminates the sometimes-unreliable ‘unsubscribe’ process built into email newsletter subscriptions.

RSS content can be read using a software called an RSS reader or an "aggregator." The user subscribes to a feed by entering the feed’s link into the reader or by clicking an RSS icon that initiates the subscription process. Many sites display a small orange icon with the universal RSS logo, or buttons that simply say "RSS" or "XML."

To give access to the XML file, a link is displayed:    or  

For other resources about RSS check out the following:

http://www.whatisrss.com/

http://en.wikipedia.org/wiki/RSS_(file_format)

http://www.feedburner.com/fb/a/feed101