Also, there's a bookmarklet at the top of the markdown-css demo that let's you apply the markdown styles to any page, which is like a harder-to-read version of readability or a quick way to see how well layed out the markup is on any page.
As a developer you may not want it - but my friends who are copywriters, editors and content strategists will LOVE this. A simple way to grab existing web content as markdown, which many are already using to write and edit their content.
The problem (at least for me on FF18/Win7) is that you can't just copy/paste the converted markdown, since it is just a display trick, not actual parsed and generated raw text.
I had made a converter that used XSLT and produced actual selectable and copy-able (?) markdown text; didn't gain much traction; I'll post it again to see if anyone's interested.
But this doesn't convert HTML to Markdown (there's already pandoc for that), it displays it as if it were Markdown. It's a clever example of what you can do with CSS, as well as perhaps poking fun at the current popularity of systems like Markdown which artificially restrict us to the IO capabilities of 70s VTs.
That makes more sense to me now. Thinking about it I see it being useful to help with some currently painful tasks like converting old wiki content that has a non-standard wiki markup syntax (or no markup at all) into markdown.
Well, maybe you want the HTML formatting without the styles or all the CSS classes. Say you wanted to do something like grab all the docs off a website and then apply your own styling or put them on an internal reference. I can see that being a good use case to allow that for open documentation.
Maybe it's like "Readbility" and those other ways of de-cluttering a web page or standardizing your style as a reader? If you have a browser that is set up to let you choose a style sheet for display, you now have a "distraction-free reading environment."
If you want plain text inside HTML isn't what the <pre> tag is for?