For example, my notes about Stable Fusion are in `~/wiki/stable-fusion.md`.
Since I have my Emacs Markdown mode tweaked to be semi-WYSIWYG, the only downside is that links between pages is a little messier than if I used wiki software. (I might tweak Emacs a bit more, to have link text in square brackets navigate to the right filename.)
Someday, these files might end up in wiki software, but I'm in no hurry, and I'm capturing and accessing the info now.