Jordi Cabot

In the Settings->Discussion page, authors of a post can use the checkbox Email me whenever – Anyone posts a comment.
But this does not send an email as well to the site admins. In blogs where you have a number of guest authors, you may want to be informed about all the new comments so you can respond (if the author is missing) or just participate in the discussion.
As a site admin myself, I was missing many comments. This means plenty of missing opportunities to engage with your audience.
To solve this situation, the plugin adds a new checkbox in the Discussion page. If checked, admins will get an alert email for new comments.

Comment Admin Notifier

Very simple plugin that doesn't try to do many things. But the one it does is very useful: as a website owner you want to make sure you're on top of all the comments in the site even comments to posts you didn't write. 

It does one thing and it does it right

With this plugin, admin users get an email alert every time a new comment is posted on ANY post in the site.

Freemius

wpdever

Bell notifications for your website users. Display an on-site notification feed with notifications created manually or through triggers (new posts/cpts, WooCommerce, new comment replies, bbPress…). 
WP Notification Bell is a custom notification and bell alert plugin for WordPress. (not push notifications and no emails) 
This plugin lets you show real-time notifications to either logged-in users, or guests, or both.
Send on-site notification campaigns and let users know about news, promotions, events, product launches… 
Or automatically notify users when you publish a new post or cpt (or when frontend users create a custom post type), or about comment replies, WooCommerce order updates…
<h4>Features</h4>
<ul>
<li>Flexible notifications : Create any type of notification with as many fields as you need. </li>
<li>Target notifications : Broadcast notifications to everyone or send to a specific user role or specific usernames.</li>
<li>New posts notifications : Send notifications to users every time you publish a new post. Custom post types included.</li>
<li>New comments notifications : Facebook-like notifications to let logged-in users receive notifications for approved comment replies to their own comment, and let post authors receive notifications for approved comments on their post.</li>
<li>bbPress notifications : New reply notification in subscribed topics for bbPress.</li>
<li>BuddyPress notifications : Display BuddyPress notifications to logged-in users.</li>
<li>WooCommerce notifications : Notify customers about each order status update.</li>
<li>Unseen notification count : Display the count of unseen notifications.</li>
</ul>
<h4>Documentation</h4>
For guides and tutorials, start from <a href="https://wpsimpleplugins.wordpress.com/documentation/" rel="nofollow ugc">WP Notification Bell documentation</a>.
<h4>Pro Features Available</h4>
<ul>
<li>New notification sound</li>
<li>New comments notifications for guest users</li>
<li>Display date on comment, buddypress and bbpress notifications</li>
<li>Custom edit WooCommerce notifications (modify content, add date…)</li>
<li>Restrict the bell display to specific user roles</li>
<li>Target notifications to logged-out guests only</li>
<li>Multiple custom post types new posts notifications</li>
<li>Move post or cpt notifications to trash automatically </li>
<li>Notification page redirection instead of drop-down box option</li>
<li>AJAX powered recent notification feed widget in real-time</li>
<li>Advanced Custom Fields placeholders (add ACF fields as default value)</li>
<li>Polylang integration</li>
<li>Display all notifications shortcode</li>
</ul>
<h4>Add-ons Available</h4>
<ul>
<li>WooCommerce back in stock notifications : Let your customers subscribe for wishlist to know when products are back in stock.</li>
<li>Dokan Multivendor Marketplace integration: Notifications for Dokan vendors (new orders, order status completed, new product reviews).</li>
<li>Asgaros Forum integration : Let users be notified on-site when they’re mentioned in a post, or when there’s a new reply in a topic they’re subscribed to.</li>
<li>WooCommerce new order notification : New order notifications for administrators and shop managers on the admin bar menu.</li>
</ul>

WP Notification Bell


Most notification plugins only allow you to manually notify people. Or, they only email notifications. This is the only plugin I can find that does on-site comment notifications. Which is nice to have even if all you have is a simple blog. Your readers should know if someone has replied to their comment (without relying on email).



I'd love it if there was one more shortcode added. A shortcode to show a list of the user's notifications. In other words, I don't think I want to use the bell and pop-up. I'd rather have a page with a shortcode that shows the notifications.



Please create an add on for Frontend PM as well.


WordPress needs this

On-site bell notifications. Display notifications custom or triggered (new posts/cpts, WooCommerce order updates, new comment replies, bbPress...)

Comment Admin Notifier vs WP Notification Bell