I wrote a post about how you can create a Related Content block which displays content related to the rendered node based on the referenced entity in that particular node. So essentially, when you write an article, you can have a special reference field to reference other articles. And then you’d get those referenced articles displayed in that block. This was done with the Entity Reference module.
But there is another way to do this, using Taxonomy. This is for those cases in which you want to show related content more dynamically – content that can become related also after the publishing of the original node. Let me tell you what I mean.
You have, let’s say, Articles tagged with red or with blue in your taxonomy. And when viewing a node tagged with red, you want a block on the side (or wherever) to display other nodes tagged with red. You can accomplish this using Views.
Starting from the premise that you already have your content tagged, go and create a block View that displays only Articles (or whatever Content Type you have tagged). Here you can of course customize your View to display all kinds of information from the nodes.
What you need to do then is add 2 contextual filters:
Content: Has taxonomy term ID and
Content: Nid. Configure the first as following:
Under When the filter value is NOT available, select Provide Default Value of the type
Taxonomy Term ID from URL. Then, check the box
Load default filter from node page, that's good for related taxonomy blocks. Next, check
Limit terms by vocabulary and under Vocabulary, check the vocabulary you want involved in this (the one which contains red and blue). Then, depending on your needs, select the appropriate choice under Multiple-value handling and apply your changes.
The second contextual filter has the purpose of excluding from the block the actual node you are currently viewing. Quickly configure it by choosing
Content ID from URL under the Provide Default Value selection and under More, check the box
Exclude. Then you can apply and finalize your view. If you save it and add the block to a page which shows a node tagged with red, the block will display other nodes that are tagged with red.
Hope this helps!