We've come full circle, first we had Org-mode as a simple plain text formatting syntax, then we had Org-Babel as a meta-programming language for literate programming.

Now we've got Markdown as a simple plain text formatting syntax, and Juypter/ipython notebooks followed, containing literate programming. Now we're seeing the rise of Markdown based literate programming.

I can't wait for a true meta-programming language to arrive on the level of Org-Babel, that's the biggest selling point of emacs!