Really Simple Syndication (RSS) is a web content syndication format and is based of the XML standard.(more information)
 

RSS is used for syndicating news by some of the major websites on the net. (slashdot, zdnet, cnet.com etc.). It's not only used for news but also personal weblogs. This allows for people and websites to share information in an easy manner. This was originally developed by Netscape Communications for the purpose of building high-end web portals, but was eventually dropped due to the decline in the portal on the Net. The first version of RSS were also deemed "extremely difficult" to use and maintain. Eventually another vendor (UserLand) picked up RSS and helped simplify it into what it is today.