I’ve created a new plugin that lets commenters enroll to receive emails when others post comments. There are other plugins that do the same thing, but I wanted something simple to install and maintain, taking advantage of the WordPress 2.0+ user role system. Any registered user can enroll to receive comments on any post or page, and it is all easily controlled from a page under the Profile section of the admin control menu.
As with my other plugins, I wrote it because it met a need of my own. I’ll often sign up to receive comments via email when commenting on friends’ (usually Movable Type) blogs. WordPress does have RSS feeds for comments, but for me an RSS subscription is too permanent a solution for the temporary need to follow a comments conversation.
I hope this plugin will help others too. Filosofo Enroll Comments