Chris Reynolds

The main purpose of this plugin is to provide a page to display documentation. Not a Wiki per se, as it’s not intented to be collaborative (although it can be), rather, it just uses Custom Post Types to separate documentation articles from the rest of your content. This plugin came as a result of my undying hatred of MediaWiki. I know BBCode and HTML and PHP and CSS and still the wiki markup just baffles me. I can never remember how to do the simplest things, like create a freaking link. Really? All I want to do is throw a <code><a href="..."></code> in there. If you’re looking at this plugin, you know what I’m talking about. When this plugin was written the WordPress plugins available for what I want to do either aren’t what I want to do, or don’t work with the latest version of WordPress. Hence this plugin.
WordPress Wiki That Doesn’t Suck uses custom post types. And that’s pretty much it. It creates a new custom post type (<code>wpwtds_article</code>) that can be accessed from the Wiki != suck menu it adds to your sidebar (!= is “not equal to” in coder jargon). Wiki articles are posted with the <code>wiki</code> slug, so your URLs will look like <code>http://mydomain.com/wiki/my-cool-article</code>.
To display your wiki articles on a page, you can either use the included template files (in the <code>/templates</code> directory), or you can use the <code>[wpwtds]</code> shortcode that’s been added in 0.9.
You can see WPWTDS in action at http://museumthemes.com/wiki/ and http://eventespresso.com/support/documentation/

WordPress Wiki That Doesn't Suck

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.

WordPress Wiki That Doesn't Suck vs BuddyPress Docs