Why do you use tags?
The tag archive
When you write posts in the same category, you can use the same tags. That will link the posts together. And when a search engine sees the link to other posts on your website they will be completely happy :)
This post of me is tagged with "Best Affiliate Marketing Program"
When the search engines find this tag, they will find the same tag on other posts on this website. And when people click this tag, they will be send over to the tag archive page on my website.
And my visitors will find there 7 related posts tagged with
"Best Affiliate Marketing Program"