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.

Andrea Porotti

Using this plugin you can attach notes to some elements in the WordPress dashboard, such as:
<ul>
<li>posts</li>
<li>pages</li>
<li>custom post types from other plugins (except the notes from this plugin)</li>
<li>users</li>
<li>plugins</li>
<li>dashboard sections</li>
<li>the whole dashboard</li>
</ul>
It can be helpfull if you manage a site with other people or just to take notes for yourself.
Features
<ul>
<li>manage notes like the standard posts by opening the Notes page from the admin menu.</li>
<li>while editing a note, use the meta box on the right to set note properties (position, color,…)</li>
<li>manage section and global notes from the admin bar.</li>
<li>manage item notes (eg. posts and pages) from the custom column in the admin pages.</li>
<li>get notes details by hovering the mouse on the “Info” links or clicking on the “I” icons.</li>
<li>add text, images and links in the note content.</li>
<li>deleted notes go to the trash, so they can be restored.</li>
<li>automatically discovers custom post types added by other plugins (eg. events, books…).</li>
<li>creates a list of the dashboard sections based on the admin menu items.</li>
</ul>
Configuration
Settings for the plugin are available on the Settings -> JAMP Notes page.
Please note:
<ul>
<li>by default the plugin data is kept after uninstall. You can choose to delete notes and settings enabling the data removal option.</li>
<li>after activation, the plugin enables notes for all the existing public post types. If you then install other plugins which create new post types, you have to manually enable them in the JAMP settings.</li>
</ul>
Permissions
The notes are currently available only for the users with the “Administrator” role. 
Each Administrator can manage all notes.
Support
If you find any errors or compatibility issues with other plugins, please let me know in the support forum. Thanks!
Privacy
This plugin does not collect or store any user data. It does not set any cookies and it does not connect to any third-party services.

JAMP Notes (Just Another Memo Plugin)

This plugin allows you to attach notes to some WordPress elements like posts, pages, dashboard sections and more.

Take Notice vs JAMP Notes (Just Another Memo Plugin)