RSS links are usually indicated by orange icons. (Image source: Feed Icons)
RSS is a text-format standard that makes it easier for content owners including bloggers to distribute their published materials. When an owner provides an RSS url, which is most of the time tagged as a ‘feed’, ‘xml’ or simply ‘RSS’, it gives an option for readers to bookmark the RSS url through “feed readers”. This helps the readers receive updates in a variety of convenient ways.
There are a lot of feed readers out there so you could manage and view updates through RSS. They are either paid or free. They could be desktop applications (examples: Feed Demon, modern browsers) or they could be online services (examples: Bloglines, Google Reader, NewsGator).
For more information, please visit the related pages on FeedBurner and Wikipedia.