RSS is basically like a new tap for your site....create one using Google Feedburner, etc and then submit it to the top Rss submission directories. After the submission everytime you update your site it tells those Rss directories to come check out your site because you did something to it. It's a great way to get a new site indexed really fast...as far as building back links go not so much. I normally just use RSS feeds for my new sites I launch and to get my backlinks indexed created quickly.....I like to create 50 or so backlinks on forums and blogs then toss all the urls of the backlinks into one Rss feed and submit the Rss feed to the top Rss directories.
Really Simple Syndication is a family of web feed formats used to publish frequently updated data. An RSS document includes full or summarized text, plus metadata such as publishing dates and authorship. Web feeds benefit publishers by letting them syndicate content automatically.
It is mainly used for blogs so their visitors don't have to revisit their website. Instead you can just view the rss feed about any new content. links2rss.com and icerocket.com are both really good to host a free rss feed.