RSS stands for Really Simple Syndication.
This is an XML file that is used to create a web feed.
A good place to figure out what RSS is used for is to look at my blog roll (list of web logs I read) at http://www.bloglines.com/public/jcnork.

As you will see, I get updates from the New York Times, CNet and Wired through RSS feeds. You will also see quite a few bloggers including Robert Scoble from Microsoft and other "industry blogs". But I also use it for updates from my family. I get notified when any of my family posts pictures on nork.com, or when my brother Michael writes in his online journal or when my favorite tech writer, Robert Cringely posts a new article.

I have been talking to PR about posting their news releases for clients as RSS feeds so that reporters can be notified instantly when a press release is posted. We will also be implementing a blog for head PhD of the Advanced Development Lab at Speedline Technologies to post information on his latest research. RSS can also be used for when our clients post newsletters on line. It can be used to be notified when a new video has been posted (vlog) or a new audio file (podcast) have been posted.

Shel Isreal is publishing a book on blogging and is posting chapters online as he goes http://redcouch.typepad.com/weblog/. He summarizes the keys to blogs as:

Blogging's Six Pillars

How it all happened is only relevant of course, if its occurrence actually matters, and in the case of blogging we see five reasons why it matters a great deal. Scoble has previously published these as Blogging's Five Pillars. We added one for good measure. Blogs are:

(1) Publishable. Anyone can publish one. You can do it cheaply and often. Each posting is instantly available worldwide.

(2) Findable. Through search engines, people will find blogs by subject, author or both. The more you post the more findable you become.

(3) Social. The blogosphere has been called on big conversation. Interesting topical conversations move from site-to-site, linking to each other. Through blogs, people with shared interests build friendships unrestricted by geographic borders.

(4) Viral. Information often spreads faster through blogs than via a news service. No form of viral marketing matches the speed and efficiency of a blog.

(5) Syndicatable. By clicking on an icon, you can get free home delivery of the RSS-enabled blogs you like into your email software. RSS lets you see if a blog you subscribe to was updated saving you search time on information that interests you. This process is considerably more efficient than the last-generation method of visiting one website at a time, then each page of that website to see if there have been any relevant changes since your last visit.

(6) Linkable. Because each blog can link to all others, every blogger has access to the tens of millions of people who visit the blogosphere every day.

7-17-05 Funny- this was my second blog post and I didn't know about spell check yet! I am number ONE on MSN for people who spell Really Simple Syndication WRONG - Realy Simple Syndication heh notice the one 'l' ;-)...