Revenue generating: yes (can be turned disabled)
Self hosted or external service: external
Setup difficulty: easy
Level of customization: high
nRelate is one of the most popular “related posts” plugins and is run through an external service which can speed up your website and save on your server resources. nRelate is highly customizable with multiple built-in templates (both text and thumbnail options) as well as the ability to add in your own custom CSS for advanced users. If you're looking to grow your site's revenue you can display promoted content mixed in with your related posts on a CPC basis. By logging into the nRelate control panel you can view performance analytics and determine how well the plugin is performing on your website. We use nRelate on this website and are very happy with the results!