Lets say on average your custom post type has at least 25 tags, and usually up to 50.
Its not enough to find "related" posts by simply whether or not they share the same tags, but instead you'd want to rank them according to how many tags they share.
I can't seem to do this by common WP_query() methods...I think I might need a whole custom query.
Unfortuantely I'm not familiar enough with WP's tables to write a query that sophisticated.
Anyone have any ideas how to do this?