I've been planning to create my own knowledgebase for a while. I believe knowledge kept secret worth nothing. Also if you're working with open source tools, it's extremely important to help others. But never found any tool convenient enough, since everything requires some weird formats to make it presentable. My notes are in Markdown format, which is pretty convenient once you set up your editor for it. I've discovered vimwiki very late, and there is an awesome helper tool for it to support Markdown -> HTML conversion.