Social Source Commons

Organize all your random notes with this easy-to-use local wiki tool. Multiple categories, freelinking, power search -- finally, all your notes in one place, and easy to retrieve. Great for to-do lists, too. For Mac OS 10 plus.

Wiki with purple numbers, transclusions, and other cutting edge experimental features.

This product no longer exists under this name. It is now Google Docs and Spreadsheets.

MoinMoin is an advanced, easy to use and extensible WikiEngine with a large community of users. Said in a few words, it is about collaboration on easily editable web pages. MoinMoin is Free Software licensed under the GNU GPL.

DokuWiki is a standards compliant, simple to use Wiki, mainly aimed at creating documentation of any kind. It is targeted at developer teams, workgroups and small companies. It has a simple but powerful syntax which makes sure the datafiles remain readable.

Wikipedia is a global and multilingual Web-based cooperative free-content encyclopedia.

Tiki Wiki CMS Groupware is a full-featured, web-based, multilingual (35+ languages), tightly integrated, all-in-one Wiki+CMS+Groupware, Free Source Software (GNU/LGPL), using PHP, MySQL, Zend Framework, jQuery and Smarty. It is actively developed by a very large international community. Tiki can be used to create all kinds of Web applications, sites, portals, knowledge base, intranets, and extranets.

Tiki offers a very large number of features "out-of-the-box", arguably more than any other Open Source Web Application. Highly configurable and modular, all features are optional and administered via a web-based interface.

Major features include a robust wiki engine, news articles, discussion forums, newsletters, blogs, file and image galleries, bug and issue trackers (form generator), a links directory, polls/surveys and quizzes, FAQs, banner management system, calendar, maps, mobile version, RSS feeds, category system, tags, an advanced themeing engine (Smarty), spreadsheet, live support, shoutbox, inter-user messaging, menu generator, advanced permission system for users and groups, internal search engine, external authentication support, and much, much more.

Now covered by Google Drive.

Web-based word processor and spreadsheet tool. Formerly Writely.

Sharable web-based document editing

OpenStreetMap is a project aimed squarely at creating and providing free geographic data such as street maps to anyone who wants them.

Professional wiki collaboration software for workgroup collaboration. ProjectForum is a wiki for small-medium teams who need to collaborate. Comes in limited free and licensed options. Also an instruction-oriented version called Course Forum (see the web site).

While articles in MediaWiki are just plain texts, SMW allows users to add structured data, comparable to the data one would usually store in a database. With this information, SMW can help to search, organise, browse, evaluate, and share the content.

Web-based suite of tools such as an RSS reader, bookmarking service, and personal wikis.

Trac is a web-based software project management and bug/issue tracking system. It provides an interface to Subversion and an integrated wiki.

Wiki with the organizational structures of companies of all sizes.

TiddlyWiki with a PHP and MySQL backend

Wiki repository of other wiki pages.

Deki Wiki is a free open source wiki and application platform for communities and enterprises.

A community project where open source software is internationalised and localised. Translatewiki.net is where Wikipedia is localised, this results in a community with localisation in over 150 active languages.

Translatewiki.net does localise other software as well when the software is freely licensed and when there is active support for the internationalisation of the software and when localisations are updated in a timely fashion

dotSUB is a browser based tool enabling subtitling of videos on the web into and from any language.

Wiktionary is a collaborative project to produce a free-content multilingual dictionary. Designed as the lexical companion to Wikipedia, Wiktionary has grown beyond a standard dictionary and now includes a thesaurus, a rhyme guide, phrase books, language statistics and extensive appendices.

FLOSS Manuals is a wiki-like platform for generating user manuals for free, libre, and open source software (FLOSS). The goal of the project is to make free software more accessible by providing clear documentation that accurately explains their purpose and use. The manuals on FLOSS Manuals are written by a community of people, who do a variety of things to keep the manuals as up to date and accurate as possible. The way in which FLOSS Manuals are written mirrors the way in which FLOSS (Free, libre open source) software itself is written: by a community who contribute to and maintain the content.

PmWiki is a wiki-based system for collaborative creation and maintenance of websites.

A Wiki supporting skins, APIs, RSS feeds, PDFs developed in Java.

An open source wiki platform based on WikiWiki for collaborative editing and creating webpages.

Live, collaborative text-editing

Mindtouch is the commercial open-source Wiki based on Deki Wiki

It's a secure accessible place online where you can post text, documents, and even photos and videos.

Cyn.in is designed to help teams to communicate faster and build collaborative knowledge by sharing and discussing various forms of digital content in a secure application. Features capabilities like wikis, social networks, blogs, file sharing repositories, micro blogs, discussion boards and other communication applications into one secure enterprise platform.

Hosted project management tool with social media features, discussions, and wiki. Scalable with free and paid for options.

free web-based Q&A platform for teachers & students, used by instructors to "easily answer questions, manage course materials, and track student participation"