I have to say, I feel much better about the commenting situation now that I’ve read all of your responses. Thank you for your assurances that you did indeed know that I wasn’t simply ignoring your comments. Also, turns out I wasn’t the only one to make the wrong assumption!
Many of you requested the name of the plug-in that I found that allows commenters to receive email notification when you reply. Here it is, my friends: Comment Reply Notification.
But don’t thank me; thank Christie, who kindly and quickly came to my rescue when I panicked and reached out to her for assistance. She rocks.
One more heads up: for the plug-in to work, you need to reply from your site, not from your blogging dashboard.
That’s all, folks! Enjoy the plug-in!
Updated to Add: This plug-in is specifically for people running WordPress on their own site/server. I cannot speak for wordpress.com sites, blogger sites, etc. You can find information about installing a WordPress plug-in here.