If your blog is run on some of the most well-known Content Management Systems, you will automatically have an RSS feed. Otherwise, you will be required to create one. Creating an RSS feed by burning it at Feedburner.com can help you get statistics on your customers or followers.
For link building, it is very simple. There are pages that will grab some of your contents without your permission. When this happens, you have to be sure that you will get a link back by submitting posts with links to several other pages on your site and placing the RSS footer plugin especially for WordPress to add some more links to your blogs for every post.