Web feeds provide web content or summaries of web content together with links to the full versions of the content, and other metadata. RSS, in particular, delivers this information as an XML file called an RSS feed, webfeed, RSS stream, or RSS channel. In addition to facilitating syndication, web feeds allow a website’s frequent readers to track updates on the site using an aggregator.
A program known as a feed reader or aggregator can check a list of feeds on behalf of a user and display any updated articles that it finds. 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 offer only RSS or only Atom.
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. Apple’s browser for the Macintosh, Safari, as well as the cross-platform Mozilla Firefox and Opera browsers have integrated support for RSS feeds.
Web-based feed readers and news aggregators require no software installation and make the user’s “feeds” available on any computer with Web access. Some aggregators combine existing web feeds into new feeds, e.g., taking all football related items from several sports feeds and providing a new football feed. There are also search engines for content published via web feeds like Feedster or Blogdigger.
On Web pages, web feeds (RSS or Atom) are typically linked with the word “Subscribe”, an orange rectangle, , or 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.