Mark

Adds a simple ‘Post-it’ widget to the Dashboard that allows you to leave yourself or other authors a note. The plugin can be configured and moved around as any other Dashboard widget. It will accept plain text or (sanitized) HTML. Only users with the capability “Edit dashboard” can edit the note.
This simple plugin is based on code from <a href="http://wpengineer.com/add-wordpress-dashboard-widgets/" title="Add WordPress Dashboard widgets" rel="nofollow ugc">WP Engineer</a> and <a href="http://rick.jinlabs.com/2009/02/01/how-add-options-to-your-wordpress-27-dashboard-widgets/" title="How to add options to your WordPress 2.7 Dashboard widgets" rel="nofollow ugc">Ricardo González Castro</a>. Leave your comments <a href="http://ideophone.org/dashboard-post-it/" title="Dashboard Post-it homepage" rel="nofollow ugc">here</a>.
Warning Your notes will be replaced by boilerplate text upon upgrading. Make sure to copy the content somewhere else before you upgrade and then paste it into the new version. Sorry about that!

Dashboard Post-it

Adds a simple 'Post-it' widget to the Dashboard that allows you to leave yourself or other authors a note.

Tomas

Plugin Name: Announcements
👉 <a href="https://tooltips.org/product/announcements/" rel="nofollow ugc">Free Download</a> | <a href="https://tooltips.org/wordpress-tooltip-plugin/announcements/" rel="nofollow ugc">Announcements Document</a> | <a href="https://tooltips.org/contact-us/" rel="nofollow ugc">404s Support</a>| <a href="https://tooltips.org/forums" rel="nofollow ugc">Support Forums</a>
Announcements is a simple & easy-to-use solution that help you to show / edit / add / delete announcements in your admin area, if user logged in your admin area, they will see all announcements first, 
if logged in users do not accept your announcements, they can not open any menu or links in your wordpress back end, the only page they can view is your announcements in back end. This plugin can help you show TOS or Notes for any users when they logged in your back end
In Announcements setting panel, you will add title, message in Announcement Message Editor, also there are options that allow users view an announcement and do not need to access the agreement, and still can open admin menu or links, all these announcements will be stored 
in Announcements menu, if users open announcements menu, they will find any messages / notes you sent to them.
Announcements setting panel, you can add / edit / delete any announcements very easy.
More amazing features are being developed and any feature request is welcome.
Feature request & Support URI: https://tooltips.org/forums 
<h3>Download</h3>
https://wordpress.org/extend/plugins/announcements/

Announcements

When users logged in admin area, they will see announcements first,  if users  did not accept announcements, they can not open any menu in back end.

Dashboard Post-it vs Announcements