FCKed Editor was created as part of a personal quest to make Intentionally Useless Websites. It's inspired by my work with Markdown and CKEditor. I wanted to create a Markdown editor that swapped out text for unicode characters and emoji in an unpredictable way.
You can highlight text in the editor and use the buttons at the top right of the page to automatically add markdown formatting.
Using the menu, you can import markdown or plain text files. It can't handle extremely large files, so if nothing appears, clear the markdown area and try again with a smaller file. You can also export an HTML file with the fcked output. Note that images will display normally in your output HTML. (The image fckin' in the preview is all done with CSS.)
You can read more about how this project was created at mary.codes.