1. You can view an outline as a document or
2. As a collection of documents, arranged hierarchically.
This duality introduced confusion in the design of outliners from the very beginning, which for me was during the late 1970s (for Engelbart it was quite a bit earlier).
Casual observers often jump to the conclusion that outliners are a breed of word processor, but that's not necessarily true. My outliners have a bit of filesystem and a bit of a word processor. And because there's only one keyboard and one mouse, this balance can get tricky. You have to choose operations to associate with each gesture.
But we've struck a good balance, imho. I don't think of Fargo as a word processor, like Word or the one in Google Docs, but it is equal to most text editing tasks that a writer such as myself has.
1. They can control the level of detail for viewing and
2. They can reorganize according to structure.
In other words they have expand/collapse and dragging move. You have control over detail and when you move something in an outliner, everything that's underneath it goes with it.
Fargo has built on the idea of an outline as a collection of documents by coming up with a way of putting an outliner-like "page break" in a the outline structure. If a headline has a type attribute then it's the title of a document, and its sub-heads form the body of the document. In this way it's acting like the Finder, with an important difference, there's no need to open a separate window to edit the contents of a document. Just expand and start editing. And moving items between documents is done with the same dragging move operation that moves a file from one folder to another.
The type attribute is important when rendering, and it will prove important when we use outlines to author Evernote stacks (they call them notebooks) or WordPress blogs, as examples.
Otherwise, in every way, the headlines with the type attributes behave exactly like outliner nodes when you're in the outliner. It's just when you're viewing the content in a non-outliner, they become the documents -- the notes in Evernote and the blog posts in WordPress.
For example, here's a screen shot of the outline I'm working in right now.
I have one post expanded, a short one, so you can see the structure of the outline.
Headlines that have a document icon instead of a wedge are the ones with type attributes. These are the documents.
The entirety of my blog is in a single OPML document stored in Dropbox.
Our CMS software, Trex, understands these conventions, and renders the website appropriately. The RSS feed for the site also keys off these markers.
This idea represents a breakthrough in outlining software, imho. It first appeared in the OPML Editor a couple of years ago, and formed the foundation for the World Outline idea, which is now fully implemented in Fargo and Trex. It's all very loosely-coupled so any outliner that emits OPML can product the content understood by Trex, and Fargo could hook into any CMS or other processor that works this way.
We're working with several other developers on software that exploits this concept, and hope to have something to demo here perhaps as soon as the Evernote conference at the end of the month (fingers crossed).
If you're a developer and you want to see for yourself, here's the OPML file for this site. You can see how it works for yourself. It's got all kinds of scripts and templates that make a real website work, so be prepared!
Questions or comments are welcome.