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. For example, in 1997 Microsoft created Channel Definition Format for the Active Channel feature of Internet Explorer 4.0, which became mildly popular. Dave Winer also designed his own XML syndication format for use on his Scripting News weblog, which was also introduced in 1997^[1].

RDF Site Summary, the first version of RSS, was created by Dan Libby of Netscape in March 1999 for use on the My Netscape portal. This version became known as RSS 0.9. In July 1999, responding to comments and suggestions, Libby produced a prototype tentatively named RSS 0.91^[2] (RSS standing for Rich Site Summary), that simplified the format and incorporated parts of Winer's scriptingNews format. This they considered an interim measure, with Libby suggesting an RSS 1.0-like format through the so-called Futures Document^[3].

Soon afterwards, Netscape lost interest in RSS/XML, leaving 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 world 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.^[4] 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^[5] in December 2000 based on a draft proposal of amendments to the specification presented by Tristan Louis^[6]. 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^[7], 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^[8] 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, David Winer called the New York Time's adoption of RSS the "tipping point" in driving the RSS format's becoming a de facto standard.

In July, 2003, Winer and Userland Software assigned ownership of the RSS 2.0 specification to his then workplace, Harvard's Berkman Center for the Internet & Society^[9].

Winer was criticized for unilaterally creating a new format and raising the version number. In response, RSS 1.0 coauthor Aaron Swartz published RSS 3.0^[10], a non-XML textual format. The format was possibly intended as a parody and only a few implementations were ever made.

In January 2005, Sean B. Palmer and Christopher Schmidt produced a preliminary draft of RSS 1.1.^[11] 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 August 2005, Jonathan Avidan launched his own project to create an "RSS 3"^[12], though apparently without backing from anyone in the RSS industry, and the project failed to take off. Sean B. Palmer and Morbus Iff, claiming to be acting on behalf of Aaron Swartz, sent a cease-and-desist notice for abuse of the RSS 3 name^[13].

In November 2005, Microsoft proposed its Simple Sharing Extensions [14] to RSS, informally named "Real Simple Synchronization" [15] by Colm Smyth.

In December 2005, the Microsoft IE team and Outlook team have announced in their blogs that they will be adopting the RSS icon, , first used in the Mozilla Firefox browser, effectively making the orange square with white radio waves the industry standard.

Quoted in the IE's RSS blog as follows: This seemed like a very good idea, so in November, Amar and I took a visit down to Silicon Valley to meet with John Lilly and Chris Beard from Mozilla to get their thoughts on it. We all agreed that it�s in the user�s best interest to have one common icon to represent RSS and RSS-related features in a browser. I�m excited to announce that we�re adopting the icon used in Firefox. John and Chris were very enthusiastic about allowing us (and anyone in the community) to use their icon. This isn�t the first time that we�ve worked with the Mozilla team to exchange ideas and encourage consistency between browsers, and we�re sure it won�t be the last.

Michael Affronti, program manager for RSS features in Outlook 12 has been blogging recently. He has some icon news also:

I'm equally excited to announce that Outlook 12 will be using the same icon to represent RSS throughout the product. We are going to be building the new icon into Outlook over the next few weeks, and think it's going to be a great way for users to see the synergy that exists between Outlook 12 and IE 7.