RSS is a family of web feed formats used to publish frequently updated digital content, such as blogs, news feeds or podcasts.

Users of RSS content use programs called feed "readers" or "aggregators:" the user subscribes to a feed by supplying to his or her reader a link to the feed; the reader can then check the user's subscribed feeds to see if any of those feeds have new content since the last time it checked, and if so, retrieve that content and present it to the user.

The initials "RSS" are variously used to refer to the following standards:

Really Simple Syndication (RSS 2.0)
Rich Site Summary (RSS 0.91, RSS 1.0)
RDF Site Summary (RSS 0.9 and 1.0)

RSS formats are specified in XML (a generic specification for data formats). RSS delivers its information as an XML file called an "RSS feed," "webfeed," "RSS stream," or "RSS channel".

Usage

Programs known as feed readers or aggregators can check a list of feeds on behalf of a user and display any updated articles that they find. It is common to find web feeds on major websites and many smaller ones. Some websites let people choose between RSS or Atom formatted web feeds; others will provide only one of the two.

Client-side newsreaders

RSS-aware programs are available for various operating systems. Client-side readers and aggregators are typically constructed as standalone programs or extensions to existing programs such as web browsers and Email readers. Many browsers have integrated support for RSS feeds. There also are other applications that can convert an RSS feed into several usenet articles, viewable through the major newsreader software such as Mozilla Thunderbird or Forté Agent.

Web-based newsreaders

Web-based feed readers and news aggregators such as Pandji's RSSreader require no software installation and make the user's feeds available on any computer with Web access.

Feed representation

On Web pages, web feeds (RSS or Atom) are typically linked with the word "Subscribe", an orange square, , or a rectangle with the letters or . Many news aggregators such as My Yahoo! publish subscription buttons for use on Web pages to simplify the process of adding news feeds.

(Wikipedia)