Markdown is a lightweight markup language, by John Gruber and Aaron Swartz created, making it the most readable and can be re-issued in the format of input and output. Inspired by this language to create already existing e-mail with the tag text. Markdown allows HTML syntax, so users can use HTML if you need to indicate yes. Markdown application originally developed by Gruber in Perl language, but is now applied to a variety of programming languages. It is the open source projects, and BSD-style license is licensed to plug-in form or content management system in the form published.