RSS is a family of web feed formats specified in xml (a generic specification for data formats) and used for Web syndication. rss delivers its information as an xml file called an "rss feed", "webfeed", "rss stream", or "rss channel". These rss feeds provide a way for users to passively receive newly released content (such as text, web pages, sound files, or other media); this might be the full content itself or just a link to it, possibly with a summary or other metadata (data describing the content). -Wikipedia

RSS 2.0 specs
http://www.rssboard.org/rss-specification

Example
http://seattletimes.nwsource.com/rss/ - Provider

http://kitchenville.blogspot.com/atom.xml - Blog example

http://64.122.107.64/westlund/ocx3/rss.asp?class=111b - Class

http://broadband.wgbh.org/amex/rss/podcast_od.xml - Podcast

http://e.my.yahoo.com/config/my_init?.intl=us&.partner=my&.from=i - Custom RSS Web reader

www.google.com/reader - Custom RSS Web reader

Web based rss readers
http://allrss.com/rssreaderswebbased.html - List of Web based readers

http://www.bennetteburks.com/NewsFeed/TopStories.aspx - Aggregate example

http://geckotech.com/westlund/rss/rss3.asp - Mark's little toy :)

RSS in Education
http://syndicateblog.petersons.com/wordpress/index.php/category/rss-best-practices/

Vista
http://ppleyard.org.uk/archives/2005/06/26/ie7-rss-nightmare.html