Justin Tadlock

Quote This is yet another quote plugin. It has been a script I’ve used on my personal blog for a few years that I figured I’d share with the rest of the WordPress community.
Basically, it lets you show quotations on your blog in one of three ways:
<ul>
<li><code>quote_this()</code> template tag for your theme template files.</li>
<li><code>[quote-this]</code> shortcode for adding it to your posts and pages.</li>
<li>Quote This widget for use in widget areas.</li>
</ul>

Quote This

Allows the user to call random quotes with the quote_this() function, [quote-this] shortcode, or Quote This widget.

Bart Stroeken

One of the fancy things within WordPress-plugins, is the availability of shortcodes. 
These codes will provide access to plugin-specific things, like displaying a gallery, or a Google-Map. 
The downside about this, is that there’s no generic overview of all available shortcodes within your environment.
This plugin will provide a list of all available shortcodes, right where the action is. When you’re editing your content. And it won’t skip the details: it’ll show you what its origin is. 
Most of all, if it’s available in the sourcecode, the documentation will be shown.
The plugin is largely based on <a href="http://php.net/manual/en/book.reflection.php" rel="nofollow ugc">PHP’s Reflection functionality</a>, and therefore only available from PHP version 5.0.0.

Shortcode Reference

This plugin will provide a list and details about available shortcodes in your current installment. All when you need it most - when editing content.

Quote This vs Shortcode Reference