What I know about RSS. Sites with Articles can give an RSS XML version of content. This allows users to use 3rd party tools to view the content as its published ( based on the toll checking the rss feed) This content can also be used on your website ( so to display latest news for example). This idea in mind , latest news shown on your website , say from CNN is a backlink to CNN site. If your content is interesting enough , #1 People will add your feed to their readers ( multiple different types , web based , windows based etc..) and #2 they wil start showing the feed on their own site , thus providing you with a backlink.
RSS (Rich Site Summary) is a format for delivering regularly changing web content. Many news-related sites, weblogs and other online publishers syndicate their content as an RSS Feed to whoever wants it.