Bloggers know about RSS, but the vast majority of Internet users do not.  May 1st will be RSS Awareness Day, created to get the word out about RSS.  RSSDay.org explains what RSS is, demonstrates how it works, and offers some examples of readers/aggregators.  Bloglines is the reader I personally use, recommended by Internet Monk.  Read up on RSS if you need to, and on May 1st, tell a friend.