This is a question I've had almost since this new website started. I found this website that was a little more helpful than the first ones I read.
But here's some excerpts:
"Feeds make it easy to manage this flow of information. Feeds can keep you updated.
You get all the latest news right away without having to search the web. You set up your preferences once and the content comes to your desktop. Your subscription is anonymous. You don't have to give out your email address. Feeds allow you to read content updates in your reader - not online."
"RSS fits all these parameters. It is a secure delivery method. RSS has a 100% delivery rate. Subscriptions are anonymous. There is no spam. If the content no longer appeals to the reader they can unsubscribe with one click - and they are actually unsubscribed!
How do people read feeds?
To receive an RSS feed, you need a newsreader - or content aggregator.
In the same way that you need a radio receiver to be able to hear radio stations, you need a feed reader to get the feed content.
There are Web-based readers like Bloglines and My Yahoo."