RSS is the abbreviation for "Really Simple Syndication." It's a way for you to view updates from your favorite websites in one convenient location rather than visiting several different websites regularly. For instance, you can subscribe to the Cumberland University Flickr Photostream RSS feed to get the latest images from CU. Other feeds, including the CU YouTube Channel and feeds from your favorite news sites, can be viewed in your RSS Reader.
There are many, many RSS Readers on the web to choose from, such as the Yahoo! Reader, the Google Reader or Feedreader. A simple web search for "RSS Reader" will reveal many more options. You may visit these sites to gain additional information about their respective readers and how they work.
For a quick tutorial on RSS feeds and the benefits they provide, check out the following video -- RSS in Plain English.