The plugin available on CodeCanyon is the standalone plugin which adds the post ranking feature to any of your themes that you have running on your site. We have tested it with a number of themes and it works perfectly.
Some themes may have minor CSS conflicts causing your voting arrows to bunch up next to your content. If this is the case simple increase the padding-right of the element surrounding the voting arrows.
This plugin can be used to make complete reddit style websites and we have not stopped there, we have created a THEME that uses the power of this plugin and much more. The theme has the ranking algorithms hard coded into the functions.php so you do not need to purchase both the plugin and the theme if you really want to make a complete reddit type website.
If however you just want the super cool, powerful voting buttons and sorting algorithms on your site, pick up a copy of the plugin today!