Alison Barrett

Take Notice lets you add one or more notice boxes across your entire site. For each notice, you can customize the following:
<ul>
<li>Whether to appear on all posts (of any post type)</li>
<li>Whether to appear on specific posts (of any post type)</li>
<li>Whether to appear on posts with certain terms (of any taxonomy)</li>
<li>Where to appear in the post (above or below the content)</li>
<li>Color of notice box (custom colors or preset palettes)</li>
<li>Whether to display the notice title with its content</li>
</ul>
Notices are a custom post type, so they can be managed and edited just like posts. You can add more than one notice at a time, and customize the above settings separately for each one. (See Screenshots for an example.)

Take Notice

Add notices to all of your posts & pages at once. Customize where and how they appear.

shawfactor

LH Dashboard Notes allow you to insert noes on your wp-admin dashboard for your users using the post editor interface. If this plugin is network activated the insertion and editing of these dashboard notes is centralised on the main site of your multisite install. Allowing you to set Dashboard notes that are viewed throughout your multisite network.

LH Dashboard Notes

Allows you to create and edit notes that appear on the admin dashboard

Take Notice vs LH Dashboard Notes