W9-RSS

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".

Another is called ATOM.The name Atom applies to a pair of related standards. The Atom Syndication Format is an XML language used for web feeds, while the Atom Publishing Protocol (APP for short) is a simple HTTP-based protocol for creating and updating Web resources.

Web feeds allow software programs to check for updates published on a web site. To provide a web feed, a site owner may use specialized software (such as a content management system) that publishes a list (or "feed") of recent articles or content in a standardized, machine-readable format. The feed can then be downloaded by web sites that syndicate content from the feed, or by feed reader programs that allow Internet users to subscribe to feeds and view their content.

A feed contains entries, which may be headlines, full-text articles, excerpts, summaries, and/or links to content on a web site, along with various metadata.

The development of Atom was motivated by the existence of many incompatible versions of the RSS syndication format, all of which had shortcomings, and the poor interoperability [1] of XML-RPC-based publishing protocols. The Atom syndication format was published as an IETF "proposed standard" in RFC 4287. The Atom Publishing Protocol is still in draft form.

Both of them are based on XML files but they have different features. Below I will explain some differences of both RSS and ATOM:
RSS 2.0 may contain either plain text or escaped HTML as a payload, with no way to indicate which of the two is provided. Atom in contrast uses an explicitly labeled (i.e. typed) "entry" (payload) container. It allows for a wider variety of payload types including plain text, escaped HTML, XHTML, XML, Base64-encoded binary, and references to external content such as documents, video and audio streams, and so forth.
RSS 2.0 has a "description" element which can contain either a full entry or just a description. Atom has separate “summary” and “content” elements. Atom thus allows the inclusion of non-textual content that can be described by the summary.
Atom standardizes autodiscovery in contrast to the many non-standard variants used with RSS 2.0.
Atom is defined within an XML namespace whereas RSS 2.0 is not.
Atom specifies use of the XML's built-in xml:base for relative URIs. RSS 2.0 does not have a means of differentiating between relative and non-relative URIs.
Atom uses XML's built-in xml:lang attribute as opposed to RSS 2.0's use of its own "language" element.
In Atom, it is mandatory that each entry have a globally unique ID, which is important for reliable updating of entries.
Atom 1.0 allows standalone Atom Entry documents whereas with RSS 2.0 only full feed documents are supported.
Atom specifies that dates be in the format described in RFC 3339 (which is a subset of ISO 8601). The date format in RSS 2.0 was underspecified and has led to many different formats being used.
Atom 1.0 has IANA-registered MIME-type. RSS 2.0 feeds are often sent as application/rss+xml, although it is not a registered MIME-type.
Atom 1.0 includes an XML schema. RSS 2.0 does not.
Atom is an open and evolvable standard developed through the IETF standardization process. RSS 2.0 is not standardized by any standards body. Furthermore according to its copyright it may not be modified.
Atom 1.0 elements can be used as extensions to other XML vocabularies, including RSS 2.0 as illustrated in a weblog post by Tim Bray entitled "Atomic RSS".
Atom 1.0 describes how feeds and entries may be digitally signed using the XML Digital Signature specification such that entries can be copied across multiple Feed Documents without breaking the signature.
Despite the emergence of Atom as an IETF Proposed Standard and the decision by major companies such as Google to embrace Atom, use of the older and more widely known RSS 1.0 and RSS 2.0 formats has continued.

Many sites choose to publish their feeds in only a single format. For example CNN, the New York Times, and the BBC offer their web feeds only in RSS 2.0 format.
News articles about web syndication feeds have increasingly used the term "RSS" to refer generically to any of the several variants of the RSS format such as RSS 2.0 and RSS 1.0 as well as the Atom format. (For example, "There's a Popular New Code for Deals: RSS" (NYT January 29, 2006))
RSS 2.0 support for enclosures led directly to the development of podcasting. While many podcasting applications, such as iTunes, support the use of Atom 1.0, RSS 2.0 remains the preferred format [5].
Each of the various web syndication feed formats has attracted large groups of supporters who remain satisfied by the specification and capabilities of their respective formats.
You can go to CNN RSS FEED page to subsribe the latest news. (we can also subsribe latest items in Amazon.com)
In order to read the RSS and ATOM, the ordinary users can use RSS Reader to read the RSS, An aggregator or news aggregator or feed reader is a client software that uses web feed to retrieve syndicated web content such as weblogs, podcasts, vlogs, and mainstream mass media websites, or in the case of a search aggregator, a customized set of search results.
Here are 7 RSS Reader software for recommandation: 7 Free Reader Software