DokuWiki!

A hierarchical note taking application, featuring rich text and syntax highlighting, storing data in a single xml or sqlite file.

TiddlyWiki is a single html file with all the characteristics of a wiki - including all of the functionality (including editing, saving, tagging and searching) and the style sheet. Because its a single file, its very portable - you can email it, put it on a web server or share it via a USB stick. It has a broad range of tools and an ever expanding plethora of plugins.

BookStack is a free and open source knowledge management platform built on PHP. The system has been built around simplicity to ensure that adding information to it is not a chore. The content structure is built on the metaphors of Books, Chapters & Pages. BookStack uses a WYSIWYG editor to create and edit content so users don't have to memorise some particular mark-up.

XWiki is a powerful Open Source collaborative platform allowing companies of all sizes to save time and money while enhancing collaboration on both team and organizational level. Being focused on efficient communication and collaboration, XWiki redefines the value of business knowledge by allowing any user to access critical information in a fast and efficient way while reducing the organizational silos.

Trusted by 8,000 businesses, Confluence is the leading collaboration software and enterprise wiki for intranets and knowledge management. Free 30-day trial.

Nuclino is the easiest way to organize and share knowledge in teams. Create real-time collaborative documents and connect them instantly like a wiki. Use the tree, board, and graph view to explore and organize your knowledge visually. It's great for meeting notes, product requirements, docs, decisions, and more.

MDwiki is a CMS/Wiki completely built in HTML5/Javascript and runs 100% on the client. No special software installation or server side processing is required. Just upload the mdwiki.html shipped with MDwiki into the same directory as your markdown files and you are good to go!

Fetchnotes helps you capture and organize short notes like books to read, ideas and shopping lists - like sticky notes for the modern age. Spend less time organizing your notes and more time acting on them! With apps on the web, mobile phone and computer, Fetchnotes is everywhere you are. Hashtags allow you to let your creativity run wild while we organize your notes for you. It's so easy our dog could use it.

Wacko Wiki is a light and handy Wiki-engine. Features: full revision control, powerful diff between revisions, access control through per-page access control lists, What You Think Is What You Get editing,integrated page commenting functionality,page watching & email notification on changes/comments,design themes (skins) support, uploads per page or global, clusters & relative addressing, automatic table of contents generation, on-the-fly correction of punctual typos & spec. characters, completely multilingual »

Referata offers hosting of semantic wikis, allowing you to add, structure and store data so it can be managed, shared, browsed and analyzed in as many ways as you choose. Free: unlimited Wiki pages and 100MB file storage. 5 Languages: English, Deutsch, Español, Português do Brasil, Russian. It can also be used to host ordinary wikis. It runs a slightly modified version of the MediaWiki software, with several extensions installed.

Lessons Learned Server is a light-weight knowledge-base web application that allows storing textual information, documents and media hierarchically within Spaces. Providing advanced search features and ease of use. Available as a downloadable server application or via cloud hosting. Based on PHP and MySQL and runs under Linux and Windows servers.

Foswiki is the free and open source enterprise collaboration platform.Foswiki is a wiki, so you and your team members can collaborate and edit pages directly in the web browser. For advanced collaboration, Foswiki lets you enter macros to automate pages and build entire applications from within your browser.