This plugin allows you to create many-to-many relationships between posts of any type: post, page, custom etc. A few example use cases:
Additionally, you can create many-to-many relationships between posts and users. So, you could also implement:
AyeCode Ltd have committed to security and maintenance updates due to this plugins requirement in our List Manager Extension.
~~I, scribu, will not be offering support (either free or paid) for this plugin anymore.~~
If you want to help maintain the plugin, fork it on github and open pull requests.
Links: Documentation | Plugin News | Author’s Site