Vocabularies for content types: each content type is associated with one or more taxonomy terms. Each node is automatically associated with the same terms.
This module provides a views argument plugin which allows you to configure a view to display related nodes by that nodes taxonomy terms and descendent taxonomy terms.
For example:
Countries vocabulary has the following terms:
USA
-> New York
Canada
Australia
NodeOne is tagged with Canada, and USA
NodeTwo is tagged with Australia, and New York
When viewing NodeOne, this module allows you to create a view which would also display NodeTwo (as it is tagged with children of one of the terms that NodeOne is tagged with).
Usage
To set up a related content block, create a view and add two arguments.
Taxonomy: Term ID
Select "Provide default argument"
"Taxonomy Term ID (and children) from URL"
"Load default argument from node page, thats good for related taxonomy blocks"
"Allow multiple terms per argument."
"Node: Nid"
Select "Provide default argument"
"Node ID from URL"
"Exclude the argument"
Then just assign your block to a node page, and you're done!