Short answer : WP — Markdown
I was kind of addicted to stackoverflow’s markdown editor and I was wondering if there is a plugin in WordPress that does the same job.
Enter WP — Markdown !!
This plug-in allows you to write posts (of any post type) using the Markdown syntax. The plug-in converts the Markdown into HTML prior to saving the post. When editing a post, the plug-in converts it back into Markdown syntax.
The plug-in also allows you to enable Markdown in comments and BBPress forums. In these instances the plug-in adds a toolbar, and preview of the processed Markdown with Prettify syntax highlighter applied (similiar to that used in the Stack Exchange websites such as WordPress Stack Exchange).
WP-Markdown stores the processed HTML, so deactivating the plug-in will not affect your posts, comments or bbPress forums.
Screen 1 : Markdown for Add / Edit Post
Screen 2 : Settings
Screen 3 : Markdown for Comments