I recently came across an interesting application, named OrgaNote. It's small (608KB), and it looks like a three-pane Outliner. However, the first pane is a rudimentary outliner, the second one is for textual information or notes, while the third pane lists all the links that a particular note contains. So, it is really more like a two-pane outliner (with an additional pane for links). As they say: "OrgaNote is a tool to organize notes. Notes are small (or large) pieces of text that can be organized in a tree structure. The key feature is the possibility to create arbitrary links between the notes to have an additionally way of organizing the notes."
Linking is done by selecting a piece of text, pressing Alt + (with + from the numeric pad) and selecting the note you want to link to from an outline that pops up. I would prefer the ability for direct links that allows for creating new links right from the editor. I can also see problems arising in a large project with many notes. But it works.
The outliner is somewhat rudimentary, allowing you to move entries down (but not up or left or right). It may be too rudimentary for inveterate outliner. You can import text files and export "extracts," text and HTML.
It also has the ability to give you a timeline for all your entries (see Website). It is kept general to allow for all kinds of uses, but the example given is a "dream journal," so it's probably best for keeping any kind of journal of specific activities or happenings.
As far as I can see, only German is available in the interface. That should not present a problem for most, as it does not have many functions. It's free.