(which, in its most recent format, stands for “Really Simple Syndication”) is a family of web feed formats used to publish frequently updated content such as blog entries, news headlines or podcasts. An RSS document, which is called a “feed”, “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 their favorite web sites in an automated manner that’s easier than checking them manually.RSS content can be read using software called a “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.
The initials “RSS” are used to refer to the following formats:
- Really Simple Syndication (RSS 2.0)
- RDF Site Summary (RSS 1.0 and RSS 0.90)
- Rich Site Summary (RSS 0.91)
RSS formats are specified using XML, a generic specification for the creation of data formats.
Before RSS, several similar formats already existed for syndication, but none achieved widespread popularity or are still in common use today, as most were envisioned to work only with a single service. The basic idea of re-structuring metadata information about web sites has been traced back at least as far as 1995, and the work of Ramanathan V. Guha and others at Apple Computer‘s Advanced Technology Group developing the Meta Content Framework (MCF). Other early work on XML syndication formats, including RDF, took place at Netscape, Userland Software, and Microsoft. For a more detailed discussion of these early developments, see history of web syndication technology.
In July 1999, responding to comments and suggestions, Dan Libby produced a prototype tentatively named RSS 0.91 (RSS standing for Rich Site Summary), that simplified the format and incorporated parts of Dave Winer‘s Scripting News format. This they considered an interim measure, with Libby suggesting an RSS 1.0-like format through the so-called Futures Document.
In April 2001, in the midst of AOL’s acquisition and subsequent restructuring of Netscape properties, a re-design of the My Netscape portal removed RSS/XML support. The RSS 0.91 DTD was removed during this re-design, but in response to feedback, Dan Libby was able to restore the DTD, but not the RSS validator previously in place. In response to comments within the RSS community at the time, Lars Marius Garshol, to whom (co?)authorship of the original 0.9 DTD is sometimes attributed, commented, “What I don’t understand is all this fuss over Netscape removing the DTD. A well-designed RSS tool, whether it validates or not, would not use the DTD at Netscape’s site in any case. There are several mechanisms which can be used to control the dereferencing of references from XML documents to their DTDs. These should be used. If not the result will be as described in the article.”
Effectively, this left the format without an owner, just as it was becoming widely used.
A working group and mailing list, RSS-DEV, was set up by various users and XML notables to continue its development. At the same time, Winer unilaterally posted a modified version of the RSS 0.91 specification to the Userland website, since it was already in use in their products. He claimed the RSS 0.91 specification was the property of his company, UserLand Software. Since neither side had any official claim on the name or the format, arguments raged whenever either side claimed RSS as its own, creating what became known as the RSS fork.
The RSS-DEV group went on to produce RSS 1.0 in December 2000. Like RSS 0.9 (but not 0.91) this was based on the RDF specifications, but was more modular, with many of the terms coming from standard metadata vocabularies such as Dublin Core.
Nineteen days later, Winer released by himself RSS 0.92, a minor and supposedly compatible set of changes to RSS 0.91 based on the same proposal. In April 2001, he published a draft of RSS 0.93 which was almost identical to 0.92. A draft RSS 0.94 surfaced in August, reverting the changes made in 0.93, and adding a type attribute to the description element.
In September 2002, Winer released a final successor to RSS 0.92, known as RSS 2.0 and emphasizing “Really Simple Syndication” as the meaning of the three-letter abbreviation. The RSS 2.0 spec removed the type attribute added in RSS 0.94 and allowed people to add extension elements using XML namespaces. Several versions of RSS 2.0 were released, but the version number of the document model was not changed.
In November 2002, The New York Times began offering its readers the ability to subscribe to RSS news feeds related to various topics. In January, 2003, Winer called the New York Times’ adoption of RSS the “tipping point” in driving the RSS format’s becoming a de facto standard.
In January 2005, Sean B. Palmer, Christopher Schmidt, and Cody Woodard produced a preliminary draft of RSS 1.1. It was intended as a bugfix for 1.0, removing little-used features, simplifying the syntax and improving the specification based on the more recent RDF specifications. As of July 2005, RSS 1.1 had amounted to little more than an academic exercise.
In April 2005, Apple Computer released Safari 2.0 with RSS Feed capabilities built in. Safari delivered the ability to read RSS feeds, and bookmark them, with built-in search features. Safari’s RSS button is a blue rounded rectangle with RSS written inside in white, . The favicon displayed defaults to a newspaper icon .
In December 2005, the Microsoft IE team and Outlook team announced in their blogs that they will be adopting the feed icon first used in the Mozilla Firefox browser , effectively making the orange square with white radio waves the industry standard for both RSS and related formats such as Atom. Also in February 2006, Opera Software announced they too would add the orange square in their Opera 9 release.
In January 2006, Rogers Cadenhead relaunched an RSS Advisory Board with a view to continuing the development of the RSS format and resolving 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. In their view, a difference of interpretation left publishers unsure of whether this was permitted or forbidden. No press account of the differences between the Winer spec and the Cadenhead spec for RSS 2.0 is included in this article’s references, though blog searches in May, 2007 found private opinions that the two specs were very similar.