RSS (Rich Site Summary; originally RDF Site Summary; often called
Really Simple Syndication) is a type of web feed which allows users
to access updates to online content in a standardized,
computer-readable format. These feeds can, for example, allow a user
to keep track of many different websites in a single news aggregator.
The news aggregator will automatically check the
RSS feed for new
content, allowing the content to be automatically passed from website
to website or from website to user. This passing of content is called
web syndication. Websites usually use
RSS feeds to publish frequently
updated information, such as blog entries, news headlines, audio,
RSS document (called "feed", "web feed", or "channel")
includes full or summarized text, and metadata, like publishing date
and author's name.
XML file format ensures compatibility with many different
RSS feeds also benefit users who want to receive
timely updates from favourite websites or to aggregate data from many
Subscribing to a website
RSS removes the need for the user to manually
check the website for new content. Instead, their browser constantly
monitors the site and informs the user of any updates. The browser can
also be commanded to automatically download the new data for the user.
RSS feed data is presented to users using software called a news
aggregator. This aggregator can be built into a website, installed on
a desktop computer, or installed on a mobile device. Users subscribe
to feeds either by entering a feed's
URI into the reader or by
clicking on the browser's feed icon. The
RSS reader checks the user's
feeds regularly for new information and can automatically download it,
if that function is enabled. The reader also provides a user
BitTorrent and RSS
RSS to email
RSS compared with Atom
9 Current usage
10 See also
12 External links
This section needs to be updated. Please update this article to
reflect recent events or newly available information. (October 2013)
Main article: History of web syndication technology
RSS formats were preceded by several attempts at web syndication
that did not achieve widespread popularity. The basic idea of
restructuring information about websites goes back to as early as
Ramanathan V. Guha and others in Apple Computer's Advanced
Technology Group developed the Meta Content Framework.
RDF Site Summary, the first version of RSS, was created by Dan Libby
Ramanathan V. Guha at Netscape. It was released in March 1999 for
use on the My.Netscape.Com portal. This version became known as RSS
0.9. In July 1999, Dan Libby of
Netscape produced a new version,
RSS 0.91, which simplified the format by removing RDF elements and
incorporating elements from Dave Winer's news syndication format.
Libby also renamed the format from RDF to
RSS Rich Site Summary and
outlined further development of the format in a "futures document".
This would be Netscape's last participation in
RSS development for
eight years. As
RSS was being embraced by web publishers who wanted
their feeds to be used on My.Netscape.Com and other early
RSS support from My.Netscape.Com in April 2001 during
new owner AOL's restructuring of the company, also removing
documentation and tools that supported the format.
Two parties emerged to fill the void, with neither Netscape's help nor
RSS-DEV Working Group and Dave Winer, whose UserLand
Software had published some of the first publishing tools outside
Netscape that could read and write RSS.
Winer published a modified version of the
RSS 0.91 specification on
the UserLand website, covering how it was being used in his company's
products, and claimed copyright to the document. A few months
later, UserLand filed a U.S. trademark registration for RSS, but
failed to respond to a
USPTO trademark examiner's request and the
request was rejected in December 2001.
The RSS-DEV Working Group, a project whose members included Guha and
O'Reilly Media and Moreover, produced
RSS 1.0 in
December 2000. This new version, which reclaimed the name RDF Site
RSS 0.9, reintroduced support for RDF and added XML
namespaces support, adopting elements from standard metadata
vocabularies such as Dublin Core.
In December 2000, Winer released
RSS 0.92 a minor set of changes
aside from the introduction of the enclosure element, which permitted
audio files to be carried in
RSS feeds and helped spark podcasting. He
also released drafts of
RSS 0.93 and
RSS 0.94 that were subsequently
In September 2002, Winer released a major new version of the format,
RSS 2.0, that redubbed its initials Really Simple Syndication.
removed the type attribute added in the
RSS 0.94 draft and added
support for namespaces. To preserve backward compatibility with RSS
0.92, namespace support applies only to other content included within
RSS 2.0 feed, not the
RSS 2.0 elements themselves. (Although
other standards such as Atom attempt to correct this limitation, RSS
feeds are not aggregated with other content often enough to shift the
RSS to other formats having full namespace support.)
Because neither Winer nor the
RSS-DEV Working Group had Netscape's
involvement, they could not make an official claim on the
RSS name or
format. This has fueled ongoing controversy[specify] in the
syndication development community as to which entity was the proper
publisher of RSS.
One product of that contentious debate was the creation of an
alternative syndication format, Atom, that began in June 2003. The
Atom syndication format, whose creation was in part motivated by a
desire to get a clean start free of the issues surrounding RSS, has
been adopted as
IETF Proposed Standard RFC 4287.
In July 2003, Winer and
UserLand Software assigned the copyright of
RSS 2.0 specification to Harvard's Berkman Center for Internet
& Society, where he had just begun a term as a visiting
fellow. At the same time, Winer launched the
RSS Advisory Board
Brent Simmons and Jon Udell, a group whose purpose was to
maintain and publish the specification and answer questions about the
In September 2004, Stephen Horlander created the now ubiquitous RSS
icon () for use in the
Mozilla Firefox browser.
In December 2005, the
Internet Explorer team and
Microsoft Outlook team announced on their blogs that they were
RSS icon. In February 2006,
Opera Software followed
suit. This effectively made the orange square with white radio
waves the industry standard for
RSS and Atom feeds, replacing the
large variety of icons and text that had been used previously to
identify syndication data.
In January 2006,
Rogers Cadenhead relaunched the
RSS Advisory Board
without Dave Winer's participation, with a stated desire to continue
the development of the
RSS format and resolve ambiguities. In June
2007, the board revised their version of the specification to confirm
that namespaces may extend core elements with namespace attributes, as
Microsoft has done in
Internet Explorer 7. According to their view, a
difference of interpretation left publishers unsure of whether this
was permitted or forbidden.
RSS is XML-formatted plain text. The
RSS format itself is relatively
easy to read both by automated processes and by humans alike. An
example feed could have contents such as the following:
<?xml version="1.0" encoding="UTF-8" ?>
<description>This is an example of an RSS
<lastBuildDate>Mon, 06 Sep 2010 00:01:00 +0000
<pubDate>Sun, 06 Sep 2009 16:20:00 +0000</pubDate>
<description>Here is some text containing an interesting
<pubDate>Sun, 06 Sep 2009 16:20:00 +0000</pubDate>
User interface of a feed reader
When retrieved, reading software could use the
XML structure to
present a neat display to the end users.
There are several different versions of RSS, falling into two major
branches (RDF and 2.*).
The RDF (or
RSS 1.*) branch includes the following versions:
RSS 0.90 was the original
RSS version. This
RSS was called
RDF Site Summary, but was based on an early working draft of the RDF
standard, and was not compatible with the final RDF Recommendation.
RSS 1.0 is an open format by the RSS-DEV Working Group, again standing
for RDF Site Summary.
RSS 1.0 is an RDF format like
RSS 0.90, but not
fully compatible with it, since 1.0 is based on the final RDF 1.0
RSS 1.1 is also an open format and is intended to update and replace
RSS 1.0. The specification is an independent draft not supported or
endorsed in any way by the RSS-Dev Working Group or any other
RSS 2.* branch (initially UserLand, now Harvard) includes the
RSS 0.91 is the simplified
RSS version released by Netscape, and also
the version number of the simplified version originally championed by
Dave Winer from Userland Software. The
Netscape version was now called
Rich Site Summary; this was no longer an RDF format, but was
relatively easy to use.
RSS 0.92 through 0.94 are expansions of the
RSS 0.91 format, which are
mostly compatible with each other and with Winer's version of RSS
0.91, but are not compatible with
RSS 2.0.1 has the internal version number 2.0.
RSS 2.0.1 was
proclaimed to be "frozen", but still updated shortly after release
without changing the version number.
RSS now stood for Really Simple
Syndication. The major change in this version is an explicit extension
Later versions in each branch are backward-compatible with earlier
versions (aside from non-conformant RDF syntax in 0.90), and both
versions include properly documented extension mechanisms using XML
Namespaces, either directly (in the 2.* branch) or through RDF (in the
1.* branch). Most syndication software supports both branches. "The
RSS Compatibility", an article written in 2004 by
and Atom advocate Mark Pilgrim, discusses
RSS version compatibility
issues in more detail.
The extension mechanisms make it possible for each branch to copy
innovations in the other. For example, the
RSS 2.* branch was the
first to support enclosures, making it the current leading choice for
podcasting, and as of 2005[update] is the format supported for that
use by iTunes and other podcasting software; however, an enclosure
extension is now available for the
RSS 1.* branch, mod_enclosure.
RSS 2.* core specification does not support providing
full-text in addition to a synopsis, but the
RSS 1.* markup can be
(and often is) used as an extension. There are also several common
outside extension packages available, e.g. one from
Microsoft for use
Internet Explorer 7.
The most serious compatibility problem is with
HTML markup. Userland's
RSS reader—generally considered as the reference
implementation—did not originally filter out
HTML markup from feeds.
As a result, publishers began placing
HTML markup into the titles and
descriptions of items in their
RSS feeds. This behavior has become
expected of readers, to the point of becoming a de facto
standard, though there is still some inconsistency in
how software handles this markup, particularly in titles. The
specification was later updated to include examples of entity-encoded
HTML; however, all prior plain text usages remain valid.
As of January 2007[update], tracking data from www.syndic8.com
indicates that the three main versions of
RSS in current use are 0.91,
1.0, and 2.0, constituting 13%, 17%, and 67% of worldwide
respectively. These figures, however, do not include usage of the
rival web feed format Atom. As of August 2008[update], the
syndic8.com website is indexing 546,069 total feeds, of which 86,496
(16%) were some dialect of Atom and 438,102 were some dialect of
The primary objective of all
RSS modules is to extend the basic XML
schema established for more robust syndication of content. This
inherently allows for more diverse, yet standardized, transactions
without modifying the core
To accomplish this extension, a tightly controlled vocabulary (in the
RSS world, "module"; in the
XML world, "schema") is declared through
XML namespace to give names to concepts and relationships between
RSS 2.0 modules with established namespaces are:
Media RSS (MRSS) 2.0 Module
RSS 2.0 Module
Although the number of items in an
RSS channel is theoretically
unlimited, some news aggregators do not support
RSS files larger than
150KB. For example, applications that rely on the Common Feed List of
Windows might handle such files as if they were corrupt, and not open
Interoperability can be maximized by keeping the file size under
BitTorrent and RSS
BitTorrent clients support RSS.
RSS feeds which provide links to
.torrent files allow users to subscribe and automatically download
content as soon as it is published.
RSS to email
See also: PubSubHubbub
Some services deliver
RSS to email inbox, sending updates from user's
personal selection and schedules. Conversely, some services
deliver email to
RSS readers. Examples of those services include
IFTTT and Zapier.
RSS compared with Atom
RSS and Atom are widely supported and are compatible with all
major consumer feed readers.
RSS gained wider use because of early
feed reader support. Technically, Atom has several advantages: less
restrictive licensing, IANA-registered MIME type,
XML namespace, URI
Relax NG support.
The following table shows
RSS elements alongside Atom elements where
they are equivalent.
Note: the asterisk character (*) indicates that an element must be
provided (Atom elements "author" and "link" are only required under
summary and/or content
lastBuildDate (in channel)
author or contributor
published (subelement of entry)
Several major sites such as
Twitter previously offered
RSS feeds but have reduced or removed support. Additionally, widely
used readers such as Shiira, FeedDemon, and
Google Reader have been
discontinued having cited declining popularity in RSS.
was removed in OS X Mountain Lion's versions of Mail and Safari,
although the features were partially restored in Safari 8. As
of August 2015,
Mozilla Firefox and
Internet Explorer include RSS
support by default, while
Google Chrome and
Microsoft Edge do not.
Additionally, reader services such as
Feedly provide synchronization
RSS readers and mobile devices.
Comparison of feed aggregators
FeedSync previously Simple Sharing Extensions
Mashup (web application hybrid)
^ "The application/rss+xml Media Type". Network Working Group. May 22,
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^ a b Libby, Dan (1999-07-10). "
RSS 0.91 Spec, revision 3". Netscape
ttem. Archived from the original on 2000-12-04. Retrieved
^ "Web feeds
RSS The Guardian guardian.co.uk", The Guardian,
London, 2008, webpage: GuardianUK-webfeeds.
^ Lash, Alex (1997-10-03). "W3C takes first step toward RDF spec".
Archived from the original on 2011-08-09. Retrieved 2007-02-16.
^ Hines, Matt (1999-03-15). "
Netscape Network: Quick Start".
Archived from the original on 2000-12-08. Retrieved 2006-10-31.
RSS Advisory Board (June 7, 2007). "
RSS History". Retrieved
^ "MNN Future Directions".
Netscape Communications. Archived from the
original on 2000-12-04. Retrieved 2006-10-31.
^ Andrew King (2003-04-13). "The Evolution of RSS". Retrieved
^ Winer, Dave (2000-06-04). "
RSS 0.91: Copyright and Disclaimer".
UserLand Software. Archived from the original on 2006-11-10. Retrieved
^ U.S. Patent & Trademark Office. "'RSS' Trademark Latest Status
RSS-DEV Working Group (2000-12-09). "RDF Site Summary (RSS) 1.0".
^ Winer, Dave (2000-12-25). "
RSS 0.92 Specification". UserLand
Software. Archived from the original on 2011-01-31. Retrieved
^ Winer, Dave (2001-04-20). "
RSS 0.93 Specification". UserLand
Software. Archived from the original on 2006-11-02. Retrieved
^ Harvard Law (2007-04-14). "Top-level namespaces". Retrieved
^ Festa, Paul (2003-08-04). "Dispute exposes bitter power struggle
behind Web logs". news.cnet.com. Retrieved 2008-08-06. The conflict
centers on something called Really Simple Syndication (RSS), a
technology widely used to syndicate blogs and other Web content. The
dispute pits Harvard Law School fellow Dave Winer, the blogging
pioneer who is the key gatekeeper of RSS, against advocates of a
^ "Advisory Board Notes".
RSS Advisory Board. 2003-07-18. Retrieved
RSS 2.0 News". Dave Winer. Retrieved 2007-09-04.
^ "2004-09-26 Branch builds". Retrieved 6 October 2014.
^ Icons: It’s still orange,
RSS Blog, December 14, 2005
RSS icon goodness, blog post by Michael A. Affronti of Microsoft
(Outlook Program Manager), December 15, 2005
^ "Making love to the new feed icon". Opera Desktop Team. 2006-02-16.
^ "Namespaces in
XML 1.0" (2nd ed.). W3C. August 16, 2006.
^ Holzner, Steven. "Peachpit article". Peachpit article. Retrieved
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2002-08-03. Retrieved 2011-08-12.
^ "Why Blogtrottr?". Retrieved 26 January 2017.
^ "Free realtime
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favourite blogs, feeds, and news delivered to your inbox". Retrieved
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^ Leslie Sikos (2011). Web standards – Mastering HTML5, CSS3, and
XML. Apress. ISBN 978-1-4302-4041-9.
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^ Frakes, Dan (February 19, 2012). "Mountain Lion: Hands on with
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^ "Subscribe to
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Retrieved January 24, 2015.
Wikimedia Commons has media related to RSS.
RSS 0.90 Specification
RSS 0.91 Specification
RSS 1.0 Specifications
RSS 2.0 Specification
History of the
RSS Fork (Mark Pilgrim)
RSS feed Tutorial with example
Web syndication technology
RSS Advisory Board—Usenet: .net
World Wide Web
World Wide Web + (-let)
Glossary of blogging
Pay per click
Spam in blogs
Uses of podcasting
Google Play Newsstand
Netscape Navigator 9
Netscape Messenger 9
Windows Live Mail
Web browser plugins
Web apps or
The Old Reader
Tiny Tiny RSS
Windows Live Personalized Experience
Adobe Media Player
Comparison of feed aggregators
History of Media aggregation
Italics indicate discontinued software.
Data exchange formats
Human readable formats