Markdown

Markdown is a lightweight and human readable markup format for text formatting created by John Gruber and Aaron Swartz. It is similar to various forms of wiki markup.

There is no formal specification for the original Markdown, and it has ambiguities that are handled inconsistently by different implementations. An attempt to improve on this situation was done (released 2014-09) by a group unrelated to the originators of Markdown, and was originally dubbed Standard Markdown until John Gruber objected to this name, and it was first renamed "Common Markdown" and later CommonMark.

Markdeep is an extended Markdown implemented in JavaScript for web use.

Specs and format descriptions

 * Official 2004 specification and markdown to HTML conversion tool
 * Draft application for text/markdown media (MIME) type
 * Markdown license
 * RFC 7763: The text/markdown Media Type
 * IANA: Registered Markdown variants
 * GitHub Flavored Markdown Spec

Software and Tools

 * Markdownpad: edit Markdown (Windows; commercial, with free-of-charge version)
 * MacDown (OS X; open source)
 * Trunk Notes: note-taking app that uses Markdown (iOS; commercial, paid)
 * Babelmark: tool to show differences in Markdown implementations (FAQ)
 * scholmd: Tools and resources for Markdown documents
 * Dillinger: cloud-enabled HTML5 Markdown editor
 * Pandoc: Document format conversion swiss-army knife
 * Announcing odpdown, a markdown-to-ODP converter
 * Writage: Markdown plugin for Microsoft Word
 * Tool to convert Google Drive documents to Markdown

Commentary

 * Switching to Markdown for Scholarly Article Production
 * What is the mime type for Markdown?
 * Discussion of media type application
 * CommonMark and the Future of Scholarly Markdown
 * How to Ditch Word
 * Markdown throwdown: what happens when FOSS software gets corporate backing?
 * Toward a better Markdown tutorial

Other links

 * Byword MultiMarkdown Guide
 * Markdown Extra - includes support for tables, definition lists, footnotes, etc.
 * Markdown Community Group
 * CommonMark
 * RFC 7764: Guidance on Markdown