Kevin Leary

Automatically link keywords and phrases to pages within a website. For example, you can make the phase “wordpress cms” automatically link to the page yoursite.com/wordpress-cms/. This is a good practice to follow for SEO, and also has the added advantage of decreasing your website’s bounce rate.

Internal Link Manager

Easily manage automated internal links throughout your website.

Allows easy access to all of your posts, to reference while writing.
Simply highlight the text you want to be the link text, and then click one of the links 
in the WP Site Links box, and the link will be created.

WP Site Links

Allows easy access to all of your posts, to reference while writing.

Internal Link Manager vs WP Site Links