Really Simple Syndication
or: RSS Feeds
Allow anyone to subscribe to updates to websites, blogs or wiki-pages, creating an interlinked 'blogosphere' and allowing any user to manage a multitude of information streams.
See also the overview article in Wikipedia at http://en.wikipedia.org/wiki/RSS
1. Definition by the Webopedia:
"Short for RDF Site Summary or Rich Site Summary, an XML format for syndicating Web content. 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, excerpts from discussion forums or even corporate information." (http://www.webopedia.com/TERM/R/RSS.html0
The Washington Post explains: “RSS lets Web sites publish free "feeds" of their content, which a program called a newsreader collects on a set schedule, displaying new headlines and links for you to read within the newsreader or, with one click, in your Web browser" (http://www.washingtonpost.com/ac2/wp-dyn?pagename=article&contentId=A55027-2004Mar13¬Found=true)
2. Definition from the Wikipedia:
"RSS is a family of Web feed formats used to publish frequently updated content such as blog entries, news headlines, and podcasts. An RSS document (which is called a "feed" or "web feed"  or "channel") contains either a summary of content from an associated web site or the full text. RSS makes it possible for people to keep up with web sites in an automated manner that can be piped into special programs or filtered displays.
RSS content can be read using software called an "RSS reader", "feed reader" or an "aggregator". The user subscribes to a feed by entering the feed's link into the reader or by clicking an RSS icon in a browser that initiates the subscription process. The reader checks the user's subscribed feeds regularly for new content, downloading any updates that it finds.
Basically there are two types of RSS readers: 1)Web based, such as the Google Reader. 2)Program based. There are lots of RSS reader programs you can download to run directly on your computer. In either case these RSS readers give you a handy interface to simultaneously monitor your favorite feeds from multiple sites and sources.. Just follow the directions for each reader." (http://en.wikipedia.org/wiki/RSS_(file_format))
Typology of RSS Feed Tools
"1. Feed Creators, which are used to automatically publish feeds when content is changed, without much additional effort; this has led to a veritable explosion in the availability of feeds
2. Feed Sources: Web sites, News, Listings, Blogs, PR announcements, Search Results, even Ebay shopping - they all have feeds now
3. Feed Finders, such as Feedster and Blogdigger, help to locate feeds of interest
4. Feed Readers, both online and offline, commonly offer bundled functionality for filtering, collating and searching feeds
5. Feed Filters and Aggregators, such as BlastFeed, help to organize a large number of feeds and consume them efficiently" (http://blog.softwareabstractions.com/the_software_abstractions/2006/12/disruptive_tech.html)