<p><a href="http://daringfireball.net/projects/markdown/">Markdown</a> is a simple
text-to-HTML converter that turns common text idioms into HTML.  The
<a href="http://daringfireball.net/projects/markdown/syntax">full syntax</a> is
available from the author's site, but here's a short summary:</p>
<ul>
<li><strong>Paragraphs</strong>: Start a new paragraph by skipping a line.</li>
<li><strong>Italics</strong>: Put text in <em>italics</em> by enclosing it in either * or
_: <code>*italics*</code> turns into <em>italics</em>.</li>
<li><strong>Bold</strong>: Put text in <strong>bold</strong> by enclosing it in two *s:
<code>**bold**</code> turns into <strong>bold</strong>.</li>
<li><strong>Pre-formatted text</strong>: Enclosing a short block of text in
backquotes (`) displays it in a monospaced font and converts HTML
metacharacters so they display correctly.  Example:
`<code><img src="foo"/></code>` displays as <code><img src="foo"/></code>. Also,
any paragraph indented 4 or more spaces is treated as pre-formatted
text.</li>
<li><strong>Block quotes</strong>: Any paragraph (or line) that starts with a <code>></code> is
treated as a blockquote.</li>
<li><strong>Hyperlinks</strong>: You can create links like this:
<code>[amazon's web site](http://www.amazon.com)</code>. That produces
"<a href="http://www.amazon.com">amazon's web site</a>".</li>
<li><strong>Lists</strong>: You can create numbered or bulleted lists by ending a
paragraph with a colon (:), skipping a line, and then using asterisks
(*, for bullets) or numbers (for numbered lists).  See the
<a href="http://daringfireball.net/projects/markdown/syntax">Markdown syntax page</a>
for examples.</li>
<li><strong>Raw HTML</strong>: Markdown will pass raw HTML through unchanged, so you
can use HTML's syntax whenever Markdown doesn't provide a reasonable
alternative.</li>
</ul>