An RSS feed gives the ability for people to follow your blog automatically by retrieving the latest content from your site via the feed, which saves them time as they don't need to physically visit your site to check.
Or you may want to embed someone else's blog on your website and therefore by adding their RSS feed so it appears in the side column on most pages of your website.
To do this, simply get the RSS URL - this is often their website name, followed by their blog extension with feed on the end. For example: http://websitedomainname.com/blog/feed
Simply enter that into the RSS Feed URL in the Widgets section of your PromoteMyPlace website for it to appear on the side column of your website.