HyperText Markup Language, commonly referred to as HTML, is the standard markup language used to create web pages. Web browsers can read HTML files and render them into visible or audible web pages.
Markdown is a text-to-HTML conversion tool for web writers. Markdown allows you to write using an easy-to-read, easy-to-write plain text format, then convert it to structurally valid XHTML (or HTML).
<h1>Hello!</h1>
# Hello!
<h2>Hello Again</h2>
## Hello Again
<em>Hello Again</em>
*Hello* or _Hello_
<strong>Hello Again</strong>
**Hello** or __Hello__
<ul>
<li>bullet list 1</li>
<li>bullet list 2</li>
<li>bullet list 3</li>
</ul>
+ bullet list 1
+ bullet list 2
+ bullet list 3
+ bullet list 4
This is an <a href="http://google.com">example link</a>.
This is an [example link](http://google.com/).
Markdown must be parsed into another format. There are a number of tools you can use to make that happen.