The concentration on external linking takes precedence in most cases leaving relevant internal linking overlooked on most websites/blogs. Integrating strong internal linking structures within your pages can provide search engines with additional keyword information that otherwise might not be indexed through the content. Using 'tagging' within posts with anchor links can do this. More on how this works after the break.
Adding 'tags' to your posts can improve the importance of keywords in posts that should be accentuated. For example, a post regarding an 'Illustrator Tutorial' should have the term 'Tutorial' weighted more heavily so that it would show up better in search results. 'Tutorial' should then be added as a 'tag' for that post. 'Tags' can also be leveraged to add synonyms which could not be mentioned in the actual post but are extremely relevant to search results.
To ensure that these 'tags' are more relevant to search engines, they are placed within anchor tags (<a>). To a search engine, anchor tags that link to content relevant to the current page are weighted higher. Therefore, the 'tag' within the anchor is relevant to that page. How you decide where the anchor links to is up to you. I would recommend leveraging a search algorithm which pulls back other posts relevant to that 'tag'. An example of this functionality has been added to my own site.