RSS stands for really simple syndication. Its a way in which you can keep a track of whats new on websites you like. You just have to subscribe for it. Publishers can now easily manage to keep their visitors updated with the new contents of their site.
How to use it?
Download a feed reader. There are lots of it on internet. Install it. Now whenever you go to a website, you see this symbol which stands for RSS feeds. Most websites have RSS feeds.
Click on that icon and your feed reader will automatically open itself. So that you can subscribe to it through your feed reader. Then keep clicking ok. Now on, all the latest stuff happening in that website will be tracked by your feed reader through feeds sent by the site. It will just give you the headlines and clicking that will take you to the website.
Try google feed reader. Its an online feed reader with better interface and great features. :)