RSS is short for RDF Site Summary or Rich Site Summary. It is an XML format for syndicating Web content. If a Web site that wants to allow other sites to publish some of its content creates an RSS document and registers the document with an RSS publisher. A user that can read RSS-distributed content can use the content on a different site. Syndicated content includes such data as news feeds, events listings, news stories, headlines, project updates, and excerpts from discussion forums or even corporate information. RSS was originally developed by Netscape (http://www.webopedia.com/TERM/R/RSS.ht
2. What is an RSS reader?
A RSS reader is a reader that is able to display any RSS and Atom news feed (XML)
3. List top 5 RSS readers that come for free?
Omea Reader, Awasu Personal Edition, Bloglines, SharpReader, RSS Bandit
According to: http://email.about.com/cs/rssfeedreader