RSS feeds are typically about informing search engines, directories and your users about new and updated content although they can also be used to detail all the pages in your website.
The good thing about RSS feeds is that you can list all your new and updated webpages and submit them to the search engines and directories to improve the inclusion of new content.
RSS feeds are essentialy XML data about the pages or information in your website e.g.
<description>Website description here</description>
<title>A Sitemap entry</title>
<description>Sitemap entry description</description>
<description>Another entry description</description>
XmlSitemapGenerator.org allows webmasters to easily create RSS sitemaps for their website without the need to hand craft them, install software or write complicated scripts.