gentlesource

This plugin creates a short URL from the blog post permalink and stores it 
in the database. The URL is displayed below the blog post along with a link 
to twitter that passes the short URL on.
You can use all short URL services that offer an API. Here are a few:
<ul>
<li>http://melt.li/</li>
<li>http://lin.io/</li>
<li>http://unrelo.com/</li>
<li>http://bit.ly/</li>
<li>http://u.nu/</li>
<li>http://tinyurl.com/</li>
</ul>

GentleSource Short URL

Automatically shortens the blog post URL.

Naman Dixit

Monetize your WordPress site with Linkrex. The official plugin allow users to earn more money.
Links monetization (displays an banner ad page when visitors click through links on your website).
<h3>Configuration</h3>
Setting up the plugin is super simple and it takes just a couple of minutes to start serving monetized links on your website:
<ol>
<li>Sign up for Linkrex (https://linkrex.net/auth/signup).</li>
<li>Install the plugin on your WordPress website.</li>
<li>Now goto the ‘Settings’ and select Linkrex Settings. </li>
<li>Now you will see there are 3 options in the Plugin settings.
<ul>
<li>Token Key: (Important)</li>
<li>Domain: (Important)</li>
<li>Patterns: (Optional)</li>
</ul>
</li>
<li>You can get your token key here (https://linkrex.net/member/tools/quick).</li>
<li>Now in second box enter your default website address or just put those domains which you do not want to short.</li>
<li>Skip the third box (only for advance users).</li>
<li>Save configuration.</li>
<li>Done !! The plugin is up and running.</li>
</ol>
Track your earnings in real-time by logging into the Linkrex dashboard.

Linkrex Monetizer

Official Linkrex.net plugin. Monetize your website easily with short links.

GentleSource Short URL vs Linkrex Monetizer