RSS (Really Simple Syndication) is a family of Web feed formats used to publish frequently updated content including, but not limited to, blog entries, news headlines, and podcasts.[2] An RSS document (which is called a "feed" or "web feed" [3] or "channel") contains either a summary of content from an associated web site or the full text. This improves crawling because instead of google having to read your full site code it will read the what you wrote and this will help you getting ads that target what you are talking about on your website.
you may want to read this to learn more about rss feeds http://en.wikipedia.org/wiki/RSS_(file_format)
RSS feed is a fast and most efficient way to - promote and get indexed new pages - get additional backlinks with high PR to your site if you submit all RSS feeds to all known RSS directories howto rss is simple - you may start with a manual feed first, if you have blog or CMS, then usually you have RSS creating modules included