An example of an RSS is Google Reader.
RSS - Computer Definition
A metadata push technology, i.e., a technology that can identify changes in data and initiate a content push to the end user, without the user having to search it out and pull it from the site.The term RSS is an umbrella term variously used to describe a number of versions of several data Web feed formats specified in Extensible Markup Language (XML) and used for syndication of Web content. Those standards include Really Simple Syndication, Rich Site Summary, and RDF Site Summary. More recently, the IETF adopted the Atom Publishing Protocol (APP), which builds on the previous RSS work.The Atom Syndication Format is described in IETF RFC 4287 (2005). See also metadata, push, Web, and XML.
(Really Simple Syndication) A syndication format that was developed by Netscape in 1999 and became very popular for aggregating updates to blogs and news sites. RSS also stood for "Rich Site Summary" and "RDF Site Summary." A source for creating RSS feeds is www.feedforall.com. See syndication format for more on syndication feeds. RSS Lineage (RSS 1.0 and RSS 2.0) There are two lineages of RSS. RSS 1.0 conforms to the W3C's RDF specification and was released from the RSS-DEV Working Group in 2000 (see RDF). In 1999, Radio Userland's Dave Winer took over Netscape's RSS 0.91, later upgrading it to Versions 0.92 and 0.94 and turning it over to Harvard in 2003 as RSS 2.0. Most newsreaders support both formats.