audacious! but maybe they're going too far? there seems to be an escaping bug on their own documentation page.

this:

is rendering for me as this:

Note that the <code> tag on the "inlinedHighlight" example does not appear in the source column. Looking at the generated DOM, I see this:

...which only raises further questions. (Why is something unescaping the < but not the  ?)

Also, before I relaxed NoScript, it rendered like this:

I also don't see how the diagram feature could practically produce good results more often than bad ones without a lot of practice, but it's pretty neat when you get it right.

I don't think this is likely to displace Markdown :) but I could see maybe trying it for a project sometime.