RSS

Rich Site Summary: Some times called RDF: A commonly used protocol for syndication and sharing of content, originally developed to facilitate the syndication of news articles, now widely used to share the contents of blogs. Mashups are often made using RSS feeds.

RSS is an XML-based summary of a web site, usually used for syndication and other kinds of content-sharing.

There are RSS "feeds" which are sources of RSS information about web sites, and RSS "readers" which read RSS feeds and display their content to users.

RSS is being overtaken by a newer, more complex protocol called Atom.