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.

For me, it’s place to leave notes about future articles, possible topics, ToDos connected with that particular WP site.
Nothing more to explain. <a href="http://kahi.cz/wordpress/wp-content/images/kahis-notes-plugin/notes-screen.png" rel="nofollow ugc">See the screenshot</a>. Making notes inside your WordPress, as simple as possible.
For more information, support, giving feedback or anything – see the <a href="http://kahi.cz/wordpress/wp-notes-plugin/" rel="nofollow ugc">official plugin’s site</a>.
<h4>Requirements</h4>
PHP 5 on your server is necessary to run this plugin.

Kahi's WP Notes

For me, it's the place to keep notes about future articles, possible topics, plans, ToDos connected with that particular WP site.

Dashboard Post-it vs Kahi's WP Notes