kenwakita

PukiWiki is a PHP-based Wiki. PukiWiki features headings, quotations, lists of various types, preformatted texts, images, footnotes, hyperlinks, smileys, and many others.
WP PukiWiki allow the WordPress author to use PukiWiki-style Wiki syntax in writing posts and pages. The screenshots give you some idea. Visit <a href="http://www.is.titech.ac.jp/~wakita/en/wp-pukiwiki/" title="WP PukiWiki main site" rel="nofollow ugc">the main site</a> for more information.
<h3>Requirements</h3>
<ul>
<li>Working PukiWiki system accessible from the Internet.</li>
<li>WP PukiWiki: WP PukiWiki uses PHP’s Curl API. Turn it on if this feature is missing on your site.</li>
</ul>

WP PukiWiki

WP PukiWiki allows the WordPress author to write articles using a light-weight syntax, instead of HTML.

Boone Gorges

CUNY Academic Commons

David Cavins

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 ifyouknowwhatimean
Features include:
<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>
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.

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.

WP PukiWiki vs BuddyPress Docs