Introductions
RSS ("RDF Site Summary") is a lightweight multipurpose extensible metadata description and syndication format. Whew, that was a mouthful! Let's take that bit by bit, shall we.
· Lightweight Much of the reason RSS has been successful stems from the fact that it is simply an XML document. You can write an RSS document by hand. With minimal effort, you can have your content-management system write it for you. Or, if you're a programmer at heart, you can utilize one of the abundant XML libraries available for your programming language of choice.
· Multipurpose While originally conceived as a portal language, RSS has been repurposed again and again for aggregation, discussion threads, home and job listings, sports scores, and more. It's not just for breakfast -- or headline syndication -- anymore.
· Extensible The recently proposed RSS 1.0 supports extension via XML namespaces. I won't go into detail here on namespaces themselves, but we'll revisit the topic throughout the tutorial.
· Metadata Metadata is data about data, answering questions like "Who wrote this?", "When was this published?", and "What is/are the topic(s) of discussion?" While the proposed RSS version 1.0 sports a rich metadata framework through RDF ("Resource Description Framework"), we'll only touch those bits of RDF that are mechanically necessary to include and not wander off beyond the scope of the task at hand.
· Syndication Now here's the fun bit. ... RSS is a snapshot-in-a-document of what you consider most interesting/important about your site at the moment. That could be your latest couple of Weblogs, up-to-the-minute sports commentary ... anything. And you make this available for the world to grab, pass on, aggregate, or publish online -- with links right back to your site for each item. That's about all I'll say about the overall picture of RSS.
I do realize that this was a rather brief overview, but since our intention is to actually create an RSS document, I'll leave further introduction to the many wonderful RSS articles already in existence; visit the Resources section below for a list.
1. What is headline syndication?
Websites that publish new content regularly usually provide a list of news headline style links to their latest content. In addition to displaying these headlines on their own websites, it is very common for publishers to make them available for syndication, so that other websites or applications can also include their headlines.Headline syndication does not deal with the full text of articles, it is simply about syndicating an automatically updating list of headlines, with each headline being a link to the item that it refers to on the publishers website.
2. What is RSS?
RSS is the name given to a simple and well-established XML format used to syndicate headlines. Once a website creates an RSS file they have created a means to allow others to syndicate their headlines.The first version of RSS (RSS 0.9) was released by Netscape in March 1999 as a format for adding news channels to their My.Netscape.Com portal.
Then in July 1999 Netscape released RSS 0.91, incorporating most of the features of a format called <scriptingNews>, which was created by UserLand. Shortly thereafter Netscape discontinued developing the RSS format, however UserLand persisted and RSS continued to grow in strength. In December 2000, the separate RSS-DEV Working Group released RSS 1.0 and Userland announced RSS 0.92.
As of April 2001, Userland is now planning RSS 0.93. Although RSS is not clearly an acronym of anything, different people have called it Rich Site Summary, RDF Site Summary and Really Simple Syndication at different times.The lack of clarity in what RSS stands for or which version is the correct one to use can seem confusing to beginners. However these issues don't need to addressed by a website wanting to create an RSS file. RSS is a very well recognised format, in fact it is often referred to as the most successful XML format to date. Some websites have a preference for one version, others create more than one RSS file and support multiple versions and a recent survey suggests that the first two versions of RSS (0.9 and 0.91) are still by far the most popular.
