A more extended discussion on comes from Dave Winer [1 2]:
Imagine a new format, like HTML, but for hierarchies. It’s called OPML, an XML-based format I designed in Y2K. You edit OPML files with an outliner. Several of them support the format now, including the one that UserLand includes in Radio. Eventually, I believe (and hope) all outliners and many other kinds of programs, ones that create and understand hierarchies, will support the format.
You can save OPML files to the Web, just like HTML files, and browse them in lots of interesting waysAnother thing outlines are good for is authoring directories, like Yahoo and DMOZ. Everyone can edit their own outlines.
Millions of people can [create directories]. It’s not hard. That’s key, because what we want to do is enable people who have deep knowledge of important areas to gather resources, organize them, and reorganize, as the world changes.
OPML directories can link to other directories, they can even (theoretically) link into other directories [this is called transclusion]. When this happens, the linked-to directory is “included” in the other. At the bottom of the page, the author’s name is different, and the suggest-a-link feature sends an email to the included directory’s author, but most readers won’t notice. It’s almost seamless.
Now, instead of having two or three all-encompassing directories, anyone with an outliner and some server space can compete to be the authority on any subject.
There’s no single root of the Web, so why should directories (like Yahoo, DMOZ, Looksmart) have single roots? And therein lies the problem with directories, and why we’re not effectively cataloging the knowledge of our species on the Internet.
A case in point. Last week I pointed to a great directory of RSS aggregators. So why not also have it available in a format that allows it to be included in other directories? I should be able to include it in the directory I keep for RSS developers. Why should I have to reinvent the wheel? Would he want me to? And maybe it fits into a directory of tools that are useful for librarians, alongside book inventory software; or in a directory for lawyers, alongside legal databases. See the point? There is no single address for a directory, every directory is a sub-directory of something, yet all the directories we build on the Internet try to put everything in exactly one place, which leads to some really ludicrous placements. My Windows software is categorized under Mac software because we were only available on Mac when it was first categorized. This one-category-for-all-information approach is a vestige of paper catalogs, not a limit of computer-managed catalogs.
I’m burning to get this idea broadly implemented. When we do, the Web will grow by another order of magnitude.
The challenge: Put all that we know on the Internet and give people the tools to present it in a myriad of ways. Let a thousand flowers bloom. No one owns the keys to knowledge. That’s Jeffersonian software. The Web, of course, was modeled after the printed page, with all its limits. This new Web is modeled after the mind of man.
Dave Winer also has written about how to implement an OPML Directory Browser.
Taken together, the ecosystems built around Blogs, RSS and OPML help solve the problem of organising unstructured content.
Tomorrow: Unstructured Content