wpdever

This plugin helps you tailor your notifications and alerts to the users interests. 
Automatically send a new post notification or email digest to all users subscribed to one of its categories, tags, or authors. 
For each post published, you might not want to send an email to your entire email list. 
This plugin will help you segment subscribers to send targeted emails. 
Send an email grouping together the latest blog posts relevant to users preferences. 
Store locally and send with the provider of your choice, or store and send with mailchimp.
Grow your mailing list and collect subscribers interests : Insert a subscription and category/tag selection form anywhere on your website. 
Send highly relevant emails automatically : Notify users when a result for one of their searches, or a post under a category or they’ve marked as relevant to their interests, has been added. 
Decide how often you want to send an email digest of published posts : Email frequency matters. You can group together a few blog posts to send at your desired frequency.
<h3>Examples</h3>
You can add a subscription form offering multiple choice categories anywhere you want, if you want to segment your users by post category or tag of interest. 
Or, for your signed up users, you can track their recent search queries to be able to notify them if a new post matching one of them has been published.
<h3>Shortcode</h3>
<ul>
<li>[target-categories-form] shortcode : Show newsletter and categories selection form</li>
<li>[target-tags-form] shortcode : Show newsletter and tags selection form</li>
</ul>
<h3>Integrations</h3>
Mailchimp : Send targeted posts to your audience using Mailchimp

Target Notifications

Let site users subscribe to categories or tags . Send post updates automatically.

Adam Walter

Admin Notice is a very simple plugin that allows you to display custom notices in the WordPress admin that is visible to all users.
Control over the notice text and styling is available from the plugin’s settings page.
Developers can use the <code>admin_notice_enable</code> hook to control the notice’s visibility on a more granular level. The following example demonstrates how to show the notice only in the “Posts” area of the admin.
<pre><code>add_filter('admin_notice_enable', function($enabled) {

 $screen = get_current_screen();

 if (isset($screen->post_type) && $screen->post_type !== 'post') {
 $enabled = false;
 }

 return $enabled;

}, 10, 1);
</code></pre>

Admin Notice

Nice Plugin!

Display a custom notice to all users in the WordPress admin.

Target Notifications vs Admin Notice