Re: Respond to forum posts by email
WordPress.com has been steadily building some of these features for blogs. However, they have yet to release any sort of plugin to be able to do this. I have a feeling it’s because it would require a fair amount of server configuration that most people wouldn’t know how or be able to do. I’ve seen people ask for them to release it, so maybe they will some day. If they do, then we’ll probably see a lot of things built on this like the forum reply as you describe. However, I haven’t seen anything else that does this in the WordPress world either.