Jenst

Add a short note about the latest changes in the current post or page.
WP Update message adds a metabox in admin post or page section. If you updated a post or page with important information you can write a note about it here.
There are a few optional settings, but the plugin works fine even without changing anything.
<h4>Settings</h4>
You can choose a style theme and more.
<ul>
<li>Published date format (if published date should be included)</li>
<li>Updated date format (if updated date should be included)</li>
<li>Position</li>
<li>HTML</li>
<li>New row replacement</li>
<li>Style theme</li>
</ul>

WP Update Message

Add a short note about the latest changes in the current post or page.

MB Creation

Popup a message on your WordPress blog is now very easy.
If you want to promote your brand new newsletter functionnality, display advertising on your homepage or get more Facebook fans you can use Simple Popup Manager to popup a message all over your content in a lovely “lightbox effect”. You can customize your message using a WP editor and of course specify the width and the height of the message box. You can limit the display of the message on either session or days basis.
<ul>
<li>Choose wether the popup will be displayed only on homepage or on every page</li>
<li>Set size, width and threshold of the popup (you can disable mobile)</li>
<li>Customize background-color and opacity</li>
<li>Popup content is just a normal WordPress editor (you can use shortcode)</li>
</ul>

Simple Popup Manager

Simple Popup Manager allows you to easily popup and display a simple message box on your WordPress front page.

WP Update Message vs Simple Popup Manager