What is RSS?
How does RSS syndication work? Say you publish a new web page about a particular topic. You want others interested in that topic to know about it. By listing the page as an "item" in your RSS file, you can have the page appear in front of those who read information using RSS readers or "news aggregators". RSS also allows people to easily add links to your content within their own web pages. Bloggers are a huge core audience that especially does this.
What does RSS stand for? There's a can of worms. RSS as introduced by Netscape in 1999 then later abandoned in 2001 stood for "Rich Site Summary." Another version of RSS pioneered by UserLand Software stands for "Really Simple Syndication." In yet another version, RSS stands for "RDF Site Summary."
History buffs might be interested that there's been some rivalry over who invented RSS. This is why we have both different names and indeed different "flavors" or versions of RSS.