OK, so what is this RSS stuff, anyway?

This email just popped into my inbox.

You have a great site and I'd like my increasingly popular progressive blog to be added to your list [at LeftyBlogs.com], but I have no idea what an rss feed is, and so am not seemingly able to register with you. Could you explain this to me so I can submit my site?

My answer:

In short, an RSS feed is a highly-formatted version of the pure content data of a website/blog.

For example, check out RSS feed for PoliticsAndTechnology.com

Same stuff, but the feed is highly structured. Most blogging systems automatically generate an RSS feed.

Basically, RSS allows others to grab the content, read it, and do stuff with it. There are lots of things people might do with it - including 'subscribe' to it using a reader similar to an email program.

For a more complete - but still understandable explanation - check out the Wikipedia.