Luminotes is a WYSIWYG personal wiki notebook for organizing your notes and ideas. It's designed for creating highly interconnected documents with many links between concepts. Streamlined visual editing allows you to create your wiki without having to use any special markup codes or switch to a separate edit mode.
Most wikis are designed for creating one large document per page. But for your own notes, this approach can grow rather unwieldy. With Luminotes, you deal with several notes all at once on the same web page, so you get a big-picture view of what you're working on and can easily make links from one concept to another.
Luminotes is open source / free software and licensed under the terms of the GNU GPL.