Hi,
I read this question: Is there any way to format (markup, markdown, rich text) text in case events?.
Looking at the comments posted, it seems that the answer to "supporting markdown" is "use the HTML rich editor".
For me, the two are not equivalent. I use Markdown everywhere so I know it by heart and, granted, it might not be as powerful as your rich-text editor, but with browser extensions, I can edit text areas with my favorite editor, something that I cannot do with rich text editors.
So is the option of Markdown something that you would consider for a future version of FB?