It's a Drupal 7 module for using the Markdownify project.
That's a two-part question.
What does Markdownify do? It's a library for converting HTML to Markdown.
What does this module do? Um, nothing. Well that's not strictly true - it's a lightweight module which makes the Markdownify class available to your projects. It just doesn't 'do' anything in itself.
Well, I wrote it so I could use Markdownify as part of a module for exporting a Drupal site into Jekyll. But you could use it whenever you want to convert HTML content to Markdown, I guess.
(Incidentally the Drupal to Jekyll export module - and accompanying blog post - is on its way)
In the usual way - bearing in mind it depends on the libraries module - then install the Markdownify library by clicking here, and place it in sites/all/libraries.
Lukas White [email protected]