intodit – A free wiki farm that includes a searchable directory of wikis on just about any topic.
ClearWiki – A private wiki geared toward businesses that includes up to ten users and 256Mb of storage in their free plan.
LittleWiki – A site that offers free private and public wiki page hosting.
Deki Express – A wiki capable of application and data mashups.
@Wiki – A free wiki hosting service that allows for both public and private wikis.
ContainU – A wiki farm with pages dedicated to people, businesses, products, and more.
on-wiki.net – A free wiki host that allows you to limit who can edit your pages.
BrainKeeper – An enterprise wiki software that includes a variety of paid plans starting at only $17/month.
Traduwiki – A wiki farm that has a special focus on translating its pages.
Zulupad – A personal online notebook with the ease of a wiki.
BusinessWiki – A wiki platform for businesses that is built on the MediaWiki platform.
Central Desktop – A wiki-based business and team collaboration tool.
Cospire – A free knowledge management system with wiki and blog functionality.
incentive – A corporate wiki, blogging and RSS platform.
Luminotes – A personal wiki-based notebook with a WYSIWYG editor. A downloadable version is also available
Metadot – A free and very easy to use wiki host.
Nexdo – A wiki for knowledge and project management that includes free and paid versions.
PicoWiki – A wiki specifically for smartphones, PDAs, iPhones and Blackberries.
Swirrl – A wiki-based collaboration tool that lets you store, share and analyze data with your team.
Seed Wiki – An ad-free wiki host that gives you the freedom to change your wiki’s layout and style.
Springnote – A personal online notebook based on a wiki platform.
Wibokr – Free wiki and blog hosting with unlimited space. A downloadable version is also available.
SmartPage – A powerful enterprise wiki and blog site.
SuperWiki – A an ad-free, simple wiki that offers addons for forum, chat, blog and calendar functions and unlimited storage.
BluWiki – A free wiki host with no ads or popups where you can publish anything.
Nuospace – An enterprise wiki with a WYSIWYG editor.
MotherWiki – A wiki farm that is aimed at getting wikis started and then helping them migrate to their own servers or wiki host.
Bitweaver – A CMS built around a wiki platform.
bLADE Wiki – A freeware personal wiki for note management.
BoltWire – A small (about 80K) and simple, but powerful, wiki engine.
ButorWiki – An open source Java wiki and CMS.
Canvas ColdFusion Wiki – A ColdFusion wiki built using Model-Glue with a powerful API.
Clearspace – A business collaboration platform that includes wiki functionality.
codeBeamer – A business collaboration suite with an enterprise wiki.
ConnectedText – A free personal wiki for managing your information, notes, and more.
daisy – A content repository and management system with a wiki front-end.
Deki – A downloadable, open source enterprise wiki.
DokuWiki – A standards-compliant wiki specifically for documentation creation.
ErfurtWiki – A PHP-based wiki.
Foswiki – An open-source wiki that supports active and passive macros to enhance usability and functionality.
trac – A wiki-based project management application.
Gazest – A community engine based on a wiki platform.
GeboGebo – A free wiki system that runs on Linux.
GroupsWiki – An open source, rails- and prototype-based WYSIWYG wiki.
Hatta Wiki – A wiki that uses a Mercurial repository to store pages.
IkeWiki – A wiki engine that supports semantic annotation by users.
ikiwiki – A wiki compiler that converts wiki pages into HTML pages.
Instiki – A wiki that supports file uploads, PDF export, RSS feeds and more, making it suitable for use as a CMS.
WikyBlog – A wiki/blog hybrid that was designed for ease of use and speed and uses an AJAX-enhanced interface.
Jacwiki – A php-based 34KB wiki that even includes CAPTCHA.
JAMWiki – A java-based wiki that doesn’t require an external database.
JSPWiki – An extensible wiki engine built around J2EE components.
KeheiWiki – A wiki engine named after a seaside town in Hawaii.
LionWiki – A file-based wiki suitable for small sites or personal journals that is extensible and templatable.
wikidBASE – An app that combines a wiki with the functionalities of a database system.
LunaWiki – A flexible and usable wiki that descended from the QwikiWiki platform.
MicKi – A micro wiki engine with minimal demands on its environment.
miniWiki – A PHP based wiki that’s aimed at single users or small groups with no anonymous editors.
MoinMoinWiki – An extensible wiki engine for collaboration on pages that are easily editable.
Perspective – A free Microsoft .Net wiki popular with big businesses.
PhpWiki – A clone of the original WikiWikiWeb written in PHP.
SmallWiki – A free and open source wiki platform for non-commercial use.
Pimki – An Instiki-based personal information manager.
PmWiki – A customizable wiki engine with hundreds of extensions.
Oddmuse – A wiki engine built in Perl and released under the GNU GPL.
PodWiki – A wiki built using the PerlPod markup.
ProntoWiki – A wiki engine built in ASP .NET with a customizable appearance and layout.
ProWiki – An open source wiki engine originally forked from UseMod.
ScrewTurn Wiki – An ASP .NET wiki engine that installs in minutes and is customizable with plugins and themes available.
Sycamore – An easy to use wiki engine available under the GNU GPL.
telepark.wiki – A business wiki engine you can try for free.
TiddlyWiki – A wiki engine that consists of a single HTML file that can be emailed, put online or even stored on a portable USB drive.
WikiPoint – Adds wiki functionality to SharePoint.
TikiWiki – A CMS that includes a wiki engine.
Traction TeamPage – An enterprise wiki and blog platform.
VQWiki – “Very Quick Wiki” is a wiki server software based on Java.
WackoWiki – A lightweight wiki engine based on WakkaWiki but with additional features.
Wala – A wiki engine designed to be friendlier and less intimidating to casual users and contributors.
WiClear – A wiki engine still in the early stages of its development.
wikepage – A wiki-blog hybrid released under the GNU GPL.
KiWi – A knowledge management wiki that includes Semantic Web elements.
Wiki Asp – A free wiki that’s easy to use.
WikiDoc – A Windows executable wiki that doesn’t require a web server or database installation and runs right from your PC.
WikiNi – A simple and effective wiki engine for internet or intranet sites.
WikiSH – A small, fast, easy wiki that will run on any Unix machine.
WikkaWiki – A standards compliant, lightweight wiki engine forked from WakkaWiki.
Zwiki – A wiki engine for the Zope 2 application platform that also works within Plone sites.
XoWiki – A wiki based on a rich text editor.
Dandelion – An experimental wiki engine that uses a revision control system for storage.
CodexWiki – An Enterprise ColdFusion wiki that uses mediawiki syntax.
reviki wiki – A Java wiki with an SVN backend.
SnipSnap – Free Java weblog and wiki platform.
Svnwiki – A wiki that stores information in a Subversion repository.
CLiki – A wiki written in Common Lisp.
PumaWiki – Simple wiki that saves all of your information in text files instead of a database.
Ogham – A wiki-like CMS that doesn’t use wiki syntax or automatic linking.
Sputnik – An extensible, full-featured wiki that’s easy to install and doesn’t require root access.
pikipiki – A small, Python-based wiki engine.
PikiePikie – A wiki engine that supports easy text input and image uploading.
wikidPad – An open source, wiki-like notebook.
Hiki – A Ruby-based wiki engine.
Swiki Swiki – A wiki engine written in Squeak. (via)