XWiki

Let’s start with the good parts: XWiki is a free and open source software platform. The idea behing XWiki is to build a software that’s easily extensible. It comes with a Wiki (surprise!), a search, a blog, a file manager, a calendar, forums and tasks. A real jack of all trades. The text markup language looks like the MediaWiki syntax, but a few extra features. You can even add CSS to parts of your document (not sure if that’s a good idea though), or even complex things like a filterable table. Unfortunately the XWiki platform is written in Java. You should probably have some experience with Java to extend it’s functionality. That’s definitely not for me.