RSS
RSS stands for "Really Simple Syndication" or "Rich Site Summary". "Really Simple Syndication" is a better description of what it actually does. RSS provides a way to deliver and receive information online WITHOUT using email.
Publishers use a continually updated XML file (the RSS) to delivery content to those that have subscribed to the "feed" (the XML file). Subscribers use "readers" to view these Feeds.
These Readers can be software loaded in the subscribers machine or can be an online service. Each time you open the software/visit the online service, the Reader will run through your RSS Feeds and list any new information that has been added by the publisher.
Think of RSS as a content delivery tool like your daily newspaper or monthly magazine, except that you get a notice (in your Reader) every time new information has been published. So instead of reading a paper that has 50 articles, you get a notice throughout the day for each one of those 50 articles.
Get more information here and here.
