RSS stands for "Really Simple Syndication". RSS is a family of web feed formats, which are utilized to publish frequently updated works.
What's a web feed?
A web feed, also referred to as "news feed", is a data that updates you on the content you're interested in. For instance, when you subscribe to DUDYE, by entering your e-mail, this keeps you updated on anything new that is posted on the site.
In short: If you subscribe to RSS, you will be informed on the latest news.