In a lengthy post earlier this month, I took a first stab at describing a word processor-less approach to document composition and formatting. A key component of that approach is the use of what has variously been referred to as "humane text," WYSIWYM (What You See Is What You Mean), and "lightweight markup"–formatting syntax that allows you to compose a document–in a completely human-readable manner, without angle brackets–in plain text in any text editor, browser text field, or device, and run it through a parser to turn it into a format more suitable for your audience, such as HTML or PDF.

Searching the Web for those who have gone before me–particularly on the matter of convincing the technologically disinclined of the benefits of weaning themselves off of their dependency on Microsoft Word (or any other word processor or even browser-based WYSIWYG editor for that matter)–I began to discern the emergence of an eerie pattern: Interest in lightweight markup seems to correspond with the rise of the so-called Web 2.0 technologies.

First, I (re)discovered the existence of other lightweight markup languages besides the one I’m used to working with, reStructuredText; the principal ones are Markdown and Textile. (I should note here that various Wiki software packages have long provided their own markup formats.) Later, I learned that Textile (or some variation of it) is used as the default formatting syntax for 37signals‘ excellent personal information management tool, Backpack. 37signals had previously created the application that made Ruby on Rails famous, and in fact employ the creator of this Web framework, David Heinemeier Hansson. Ruby on Rails’ exploitation of the Ajax technologies in large measure has marked it as a kind of technological standard bearer of Web 2.0, as suggested by the first product offering from Adaptive Path (a key promoter of the Web 2.0 idea), Measure Map, also created on Ruby on Rails.

As if that weren’t enough, the other major lightweight syntax project, Markdown, was created by Mac-oriented blogger John Gruber, who is employed by Joyent, a company whose work appears heavily to leverage Ruby on Rails and Ajax, and which had previously acquired TextDrive, the company whose founder is responsible for Textile. The circle seems complete.

So where does lightweight markup fit into Web 2.0 conceptually speaking? It might be worth explaining what I mean by Web 2.0, since there seems to be no commonly accepted definition of this relatively new industry buzzword. One intriguing definition I came across (I forget where): "Web applications that don’t suck." For those inclined to a more formal explanation, I recommend Tim O’Reilly’s (his company coined the phrase) treatment of it, as well as Paul Graham’s reflections (though in light of the present topic, I can’t help but think that his suggestion to create a Web-based version of Microsoft Office is misguided).

Aside from noting that it was made possible in part by the mainstreaming of broadband Internet access (Ajax-laden applications tend to take a long time to load otherwise), maybe the best way to gain an understanding is to list a few of the more prominent examples:

• Google Maps, but especially the so-called "mashups" like chicagocrime.org and housingmaps.com, which use the Google Maps open API map data from a third source onto Google Maps’ super-responsive, desktop app-like interface, which popularized Ajax overnight
• del.icio.us, the "social bookmarks" manager, which aggregates the "tags" that users apply to their favorite sites and makes the results of that tagging available to all other users, allowing them to take advantage of the network effects that redound as a result of mass use of the site.
• Wikipedia, the collaborative encyclopedia, which until recently was open to editing by all Internet users, even without requiring registration of a username. As Graham notes, "experts have given Wikipedia middling reviews, but they miss the critical point: it’s good enough."

One of the common threads of these applications is their embrace of openness. In many cases this means using Open Source software and participating in Open Source projects, in recognition of the effectiveness of that approach in creating quality software in a short period of time. But perhaps more importantly it means open standards, including Web standards like XHTML and CSS, as well various XML dialects for sharing data between applications via Web services.

It is probably this fundamental quality of openness which has motivated the interest in lightweight markup among the Web 2.0 cognoscenti. Plain text is among the most platform-neutral technologies imaginable, requiring no special software to use, no special browser plugins, very minimal hardware requirements. It’s agile; when used with appropriate parsers, input can be repurposed for any number of uses, "decoupling" it, so to speak, from dependency on any particular application, just as Web 2.0 technologies tend to do with their functionality.