Peter

<p>Add notes on the “edit post” and “edit page” screens’ sidebars in WordPress 2.8 and up. When used with <a href="http://www.theblog.ca/wordpress-collaboration-emails" title="From Peter's Useful Crap" rel="nofollow ugc">Peter’s Collaboration E-mails</a> 1.2 and up, the notes are sent along with the e-mails in the collaboration workflow.  There is also a general and private notes system on the dashboard.</p>
<h4>Features</h4>
<p>On its own, this plugin adds a panel to the sidebar of the add and edit post / page screens so that users can add notes for themselves or others and keep track of these notes. Whenever you save a post, you can type a note to be displayed along with the post in the edit view.</p>
<p>On the dashboard, there’s also a summary of the most recent notes. By default this shows notes by all people on relevant posts / pages. There is also a general and private notes system.</p>
<p>For an illustrated explanation on how the plugin works with <a href="http://www.theblog.ca/wordpress-collaboration-emails" title="From Peter's Useful Crap" rel="nofollow ugc">Peter’s Collaboration E-mails</a> to send e-mails with the notes, see <a href="http://www.theblog.ca/wordpress-post-notes" title="From Peter's Useful Crap" rel="nofollow ugc">this page</a>.</p>
<h4>Translations</h4>
<ul>
<li>fr_FR translation by Denis Rebaud</li>
<li>pt_BR translation by Murillo Ferrari</li>
<li>es_ES translation by Karin Sequen</li>
<li>ja translation by Kazuhiro Terada</li>
<li>pl_PL translation by Michal Rozmiarek</li>
<li>nl_NL translation by Rene of http://wpwebshop.com</li>
<li>sv_SE translation by Karin Lindholm</li>
<li>ru_RU translation by Alexander Maltsev</li>
<li>tr_TR translation by Berkay Unal of http://www.berkayunal.com</li>
<li>da_DK translation by Lars Andersen</li>
<li>de_DE translation by Tobias Karnetzke</li>
<li>lt_LT translation by Vincent G of http://www.host1free.com</li>
<li>it_IT translation by Ludo</li>
<li>cs_CZ translation by Michal Kuk</li>
<li>sk_SK translation by Patrik Žec (PATWIST) of http://patwist.com</li>
<li>he_IL translation by Itamar Megged</li>
</ul>
<h4>Requirements</h4>
<ul>
<li>WordPress 3.2 or higher</li>
</ul>


Peter’s Post Notes

This plugin makes it easier to work with multiple person.

magnificent plugin

Add notes to the "edit post" and "edit page" sidebars. Collaborators can also share notes on the WordPress dashboard.

Boone Gorges

CUNY Academic Commons

David Cavins

<p>BuddyPress Docs adds collaborative work spaces to your BuddyPress community. Part wiki, part document editing, part shared dropbox, think of these Docs as a BuddyPress version of the Docs service offered by the Big G <em>ifyouknowwhatimean</em></p>
<p>Features include:</p>
<ul>
<li>Docs that can be linked to groups or users, with a variety of privacy levels</li>
<li>Support for fully-private document uploads</li>
<li>Doc taxonomy, using tags</li>
<li>Fully sortable and filterable doc lists</li>
<li>TinyMCE front-end doc editing</li>
<li>One-editor-at-a-time prevention against overwrites, plus idle detection/autosave</li>
<li>Full access to revision history</li>
<li>Dashboard access and management of Docs for the site admin</li>
</ul>
<p>This plugin is in active development. For feature requests and bug reports, visit http://github.com/boonebgorges/buddypress-docs. If you have translated the plugin and would like to provide your translation for distribution with BuddyPress Docs, please contact the plugin author.</p>


BuddyPress Docs

I used it on a project for a client several years ago and it worked like a charm. Also, it was well-maintained.

Peter’s Post Notes vs BuddyPress Docs