RSS is a dialect of XML. All RSS files must conform to the XML 1.0 specification, as published on the World Wide Web Consortium (W3C) website.
RSS allows you to see when sites from all over the internet have added new content. You can get the latest headlines and articles (or even audio files, photographs or video) in one place, as soon as they are published, without having to remember to visit each site every day.
It takes the hassle out of staying up-to-date, by showing you the very latest information that you are interested in.