SEO Smart Links plugin is a must-have for a SEO-conscious blog. Why? Because it makes internal link building easier and automatic.
Like if I want every mention of the word “make money online” (edit: the plugin added that link! 😀 ) on this blog automatically links to this blog homepage, I will just set it there and WordPress will comply automatically. Even category pages can be automatically linked once the category name is mentioned on the post, all you need is to configure it on the plugin settings page.
You still have some control on the plugins, like setting the maximum number of links it will generate in a post and the maximum links for each keyword. It also have exclude option where you can specify pages and posts you don’t want links to be generated automatically.
And one more thing, you are not tied to simple internal linking. You can also use it for external linking. Like if I want every mention of a word to link to an affiliate link or an external site, it’s possible.
You can download SEO Smart Links here. It’s compatible up to WordPress 2.9.1.