Markdown is a lightweight and easy-to-use syntax for styling all forms of writing on the GitHub platform. What you will learn: How the Markdown format makes styled collaborative editing easy How Markdown differs from traditional formatting approaches How to use Markdown to format text How to leverage GitHub's automatic Markdown rendering How to apply GitHub's unique Markdown extensions Markdown is a way to style text on the web.
This is intended as a quick reference and showcase. For more complete info, see John Gruber's original spec and the Github-flavored Markdown info page. Note that there is also a Cheatsheet specific to Markdown Here if that's what you're looking for. You can also check out more Markdown tools.