OPML DeMystified

In a two day span I was asked what OPML was by my friend Brian and during a discussion at the Central Iowa Bloggers meeting.

There are several definitions floating around the web but none that pass the mom test.

Wikipedia says:

OPML (Outline Processor Markup Language) is an XML format for outlines. Originally developed by Radio UserLand as a native file format for an outliner application, it has since been adopted for other uses, the most common being to exchange lists of RSS feeds between RSS aggregators.

The OPML specification defines an outline as a hierarchical, ordered list of arbitrary elements. The specification is fairly open which makes it suitable for many types of list data.

That’s not going to cut it. How about the RSS Glossary?

OPML an XML-based format that allows exchange of outline-structured information between applications running on different operating systems and environments.

That’s getting better… You could read the spec, but I even find that boring.

To make it as simple as possible, think of OPML as an outline. You remember outlines from writing college papers, right? You used (actually, you wrote the paper and then the outline) them to organize your thoughts before writing a paper.

In a sense OPML is the same thing only it is generally used to organize online, web based content. It allows people to easily exchange digital information in an open format that can be used in and by many webservices.

Oops, that’s starting to sound technical. Let’s get back to the idea of organization and sharing information. The most common use of OPML files are to organize RSS feeds.

For instance, I wanted to organize all of the Central Iowa Bloggers together into an accessible format so we could all easily subscribe to each other’s blog feeds. So I created the OPML file and now we can all subscribe to it in our feed readers. With one click I am able to subscribe to all the Central Iowa Bloggers’ blogs.

Generally one must ‘Import’ an OPML file into their feed reader. For some feed readers, like Google Reader, you must download the OPML file and then import it. Others allow you to import directly from the URL. But once you have imported the file you will see it in your feed reader and it will show up like a normal feed.

Bloglines – Import OPML
Google Reader – Import OPML
Newsgator – Import OPML
Internet Explorer 7 – Import OPML
Rojo – Import OPML

There are thousands of uses for OPML files. If you want to organize and share digital information, OPML is definitely a viable solution.

If you have any questions or need clarification leave me a comment and I will answer.

Note: If you would like to create an OPML file, build a web application from an OPML file, or find out more about this type of new media let us know.

Update: Amy Bellinger, who commented below, wrote a book (PDF) called Getting Acquainted with OPML for O’Reilly. I will let you know if it’s a useful resource after I get a chance to read it.

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