RSS stands for Really Simple Syndication. It's an easy way for you to keep up with news and information that's important to you, and helps you avoid the conventional methods of browsing or searching for information on websites. Now the content you want can be delivered directly to you without cluttering your inbox with email messages. This content is called a "feed."
Some browsers, such as the current versions of Firefox and Safari have built in RSS readers. If you're using a browser that doesn't currently support RSS, there are a variety of RSS readers available on the web; some are free to download and others are available for purchase.