Effective communication between posts, pages, data types, users, all this can be embedded in WordPress with a plugin called Posts 2 Posts. This solution allows you to create many relationships between posts of any type: page, record, etc.
A few usage examples:
installed manually curated lists related posts
series of posts
products for retail
In addition to this functionality, you can create many relationships between posts and users. So, you can realize:
favorite posts of users
multiple authors in a single message