EEVL has created one of the best overviews of RSS I’ve seen yet: “RSS — A Primer for Publishers and Content Providers”:
“This document is aimed at publishers and content providers with the intention of introducing & explaining the concepts behind RSS and addressing some commonly expressed concerns. It is primarily intended for a non-technical audience who require an overview of RSS in order to allow them to make decisions regarding the possible use of the technology. However, the guidelines do provide recommendations for good practice, case studies on RSS production and links to tools and specifications which will provide useful starting points for those tasked with actually producing RSS feeds.”
If you are just now trying to figure out what this all means, this is definitely the place to start.