Zim - A Desktop Wiki
Zim is a graphical text editor used to maintain a collection of wiki pages. Each page can contain links to other pages, simple formatting and images. Pages are stored in a folder structure, like in an outliner, and can have attachments. Creating a new page is as easy as linking to a nonexistent page. All data is stored in plain text files with wiki formatting. Various plugins provide additional functionality, like a task list manager, an equation editor, a tray icon, and support for version control.
Zim can be used to:
Zim handles several types of markup, like headings, bullet lists and of course bold, italic and highlighted. This markup is saved as wiki text so you can easily edit it with other editors. Because of the autosave feature you can switch between pages and follow links while editing without worries.
Although zim now exists for over 3 years there is no "1.0" version yet. This does not mean that the application is particularly un-stable (although making backups is always good practice) or only usable for linux gurus. But it does mean that the feature set is not yet complete (of course everything described in the manual is implemented). New releases are announced through freshmeat, subscribe there to get the latest updates.
This website was written in Zim !