RSS seems to be on the tip of every tongue nowadays, and I’ve been realizing not everybody has a clear idea of “what” it is, or how it differs from Atom (that “other feed type”). This post hopefully clears up the mess in everybody’s mind about the differences between RSS and Atom and is loosely based on the comparison chart here and Atom 1.0′s specification, dated July 12.
Okay, so what are these things?
Both RSS and Atom present a webmaster with ways to give users access to his content without making the user load up their webpage. While this is a very loose scope, many other uses arise from this simple activity – examples: it becomes possible to have headlines from other websites in your own, to aggregate news with an application so you can catch up on them later, to follow what a load of websites are talking about with one swoop, etc. Basically, the reason for all the hype is that possibilities are in fact, endless (well, you know. Almost endless).Anyway, i’ll be bold enough to assume you have a clear idea of what RSS and/or Atom is and the last paragraph was boring enough to skip. Let’s get on to what was promised. A comparison between the two, because that seems to be important:
Comparing RSS and Atom
Put simply, they are similar and accomplish the same things. However, most people seem to forget about Atom and go with RSS all the time, even if the recently proposed Atom 1.0 standard does – from a technical standpoint – seem to be a little more logical than RSS. Here are the main differences:- While RSS has two main publishing protocols, Atom has one standardized approach. This waives off some of the interoperability issues between using both the Blogger protocol and MetaWeblog (the two protocols for RSS publishing). Best approach: Atom
- When it comes to required content on a feed, Atom is much more restrictive, needing more data in order to be valid. RSS has a more loose approach. This has generated some discussion: ultimately, I like how Atom requires “last update” timestamps, but I like how RSS isn’t as restrictive to be standard. Best approach: Both have their strong side
- RSS requires escaped HTML or plain text, while Atom allows for other forms of data. This increases human-readability of an Atom feed, even though it complicates the publishing process (because you have to specify the kind of data you’re publishing). Best approach: RSS (assuming that a feed is meant for automated consumption – human readability is a task for the reader or aggregator)
- Atom clearly distincts partial content from excerpts, while RSS doesn’t. This clearly makes a difference, because there’s no way to know when an item on an RSS feed is a full story or an excerpt (that requires loading the original page in order to continue reading). Best approach: Atom, clearly.
- Autodiscovery is standardized in the Atom specification, whereas in RSS there have been several ways to discover feeds, to this date. Best approach: Atom even though it is not a grave situation for RSS.
- Aggregating and extracting content is one of the most important issues, and the one that clearly gives Atom an advantage. RSS allows content only inside a single monolithic rss document including several entries. Atom on the other hand allows for single Atom Entry documents, that make syndicating, aggregating or reusing single entries of a feed a much easier process. Best approach: Atom
Wrapping up
Reading about these differences (many, a little more technical, are not covered in this article) made me realize Atom 1.0, drafted 12th July, may in fact be a better mechanism to allow for content syndication, even though the business and software machine is oiled on the RSS concept. This doesn’t mean we’re all going for a sub-par technology because other (improved) versions of RSS are bound to emerge in due time, but for now, Atom does seem like the best-fit choice.Technical users may want to follow the following two links for more relevant information about both Atom and the differences between it and RSS 2.0:
I hope this post clears up some of the confusion between the two formats. Feel free to drop me an email (or leave comments) if you have any comments, suggestions, or questions.
Update: Scott mentions in the comments something in forgot in my wrap-up paragraph. According to the RSS roadmap, RSS 2.0 is the “final” version of RSS, meaning future revisions of the standard will emerge under a different name.
