This document provides an introduction to RSS (Really Simple Syndication) including: 1) RSS allows websites to syndicate their content so that updates can be viewed in an RSS reader without visiting the site directly. 2) RSS uses XML formatting to separate content from presentation and make feeds viewable across different readers. 3) RSS has evolved since its creation in 1997 and is now widely used for everything from news sites to blogs, academic research, and social media like Flickr and YouTube.