rss feed are like the little scrolling text on the bottom of news. Sorry, but that all I really can explain. In forums, they will scroll resent posts.
Okay, from wikipedia:
Web feeds provide web content or summaries of web content together with links to the full versions of the content, and other metadata
. RSS in particular, delivers this information as an XML
file called an RSS feed, webfeed, RSS stream, or RSS channel. In addition to facilitating syndication, web feeds allow a website's frequent readers to track updates on the site using an aggregator