RSS has been explained beautifully by programmers with PhD's from Stanford in terms only Masters-students from Stanford can understand. We are going to give it a shot in a learn-by-doing format.
RSS is a way to receive automatic updates from websites and blogs. The updates are content, like articles from the New York Times. To receive the updates you need a place to read them, and one of the easiest is Google Reader.
Create an account with Google and you'll be able to search and add feeds from many of the websites you visit during the day, from ESPN to Investors Business Daily to the National Enquirer. Most large sites have RSS feeds.
How does RSS help you? It brings all your online information into one place where you can read the headlines and click-through if the article interests you. The content is updated automatically from the sites, often almost instantly.
Recommendation: Gather together at least 5 sites you normally visit and throw them into your Google Reader. Now you're pinging one site instead of five. Entering 1-2 sites is a waste of time - it makes RSS an extra step. 5+ and you're saving time. 20 or more and it's information-overload and time to get back to work.