OutWiker is often advertised as a personal wiki. On the Web site you find: "OutWiker is designed to store notes in a tree. Such programs are called "outliner", personal wiki, or tree-like editors. OutWiker's main difference from the other similar programs is keeping the tree of notes in the form of directories on disk, and encouraging changing the base by external sources and programs." This is at the very least misleading. Outliners and tree-like editors fall into a different category from wikis.
This is not to say, of course, that a program may not fall into both categories. Wikidpad obviously does both. And you might think that OutWiker does so as well.
However, I do not think that it really is a wiki. My main reason is this: While OutWiker allows for internal links, they are really just file links enclosed in double square brackets, like this: "[[other page -> /Projects/Outwiker/Screenshots/Page Example - 21]]". This is really cumbersome and has none of the advantages of wikilinks (or free links). Straight file links would have been preferable. You could probably simplify it with an AhK script, but it would still be much more complicated than it should be.
I like the idea that the entries are text files, and I find much of the wiki markup acceptable, but I cannot live with the way links are implemented. Perhaps others can ...
1. There are other ways of doing the link, but they are all overly complicated, and I could not get most of them to work (which may have had to do with the fact that I ran the program in Parallels).