Who needs auto related posts?

I thought I wanted an automatically generated related posts section at the bottom of each post, but then I read that this chews up a lot of database access and time. But I still wanted related posts.

This plugin works simply and allows me to choose for each post the related posts I want to show. Just search for a key word and choose the posts you want.

I have only one wish. It would be great if the keyword could be tags or categories, as that would simplify finding posts that are related.