I do most of my writing in a text editor and format it with Markdown—articles, essays, blog posts, and much more. I’m not the only one, either. Not only do countless people write with Markdown, but there are also more than a few publishing tools built around it. Who’d have thought that a simple way to format web documents created by John Gruber and the late Aaron Schwartz would become so popular?
Source : 4 open source Markdown editors