[mikhailfranco]

I agree about markdown, but the only awkward implementation issue is nested syntax: what markup is parsed inside various other outer markup forms?

Italic headings? Bold links? Nested lists - how many levels? Code in list? How do paragraphs interact with lists? There are many opinions and many leaky implementations of those opinions. Newlines? Embedding HTML in Markdown !?!?

It all seems so sad, because (X)HTML nailed most of these issues a very long time ago. But HTML implementations were sloppy from the outset. And XML was born with inherited bloat, then got ever more complex over time (modular specs, XLink, XPath, XSLT, DTD -> XML Schema, ...)

With Markdown, it is relatively easy to introduce some recursion into the parser, but for what spec? In what contextual cases? At what cost?