Private Comments was designed as a WordPress plugin for private or restricted comment threads.
The concept mattered because it was not just another comment-style add-on. It centered on permissions, restricted discussion workflows, packaging, and how to graft more private communication patterns onto WordPress without turning the whole site into a forum.
Even unfinished, it is still a useful example of plugin product thinking around user capabilities, conversation models, and WordPress-specific architecture rather than only surface-level theme customization.