RSS is a relatively new technology that also goes by the name "Web Feeds" and "Live Bookmarks". It allows you to "subscribe" to an RSS feed in your RSS reader. Then you use your RSS reader to check many sites at the same time and you are presented headlines from the sites that are new since you last checked. It's a great way to keep tabs on frequently updates sites like news sources, blogs, or BakerNeighborhood.org.
The best news is that if you are reading this, you probalby already have an "RSS reader" accessible. You can use a variety of applications including the Mozilla Firefox or the Apple Safari browsers or even online services. This is all explained in greater detail in the Wikipedia.