I would love to hear something from the author of the wiki about how he uses those notes, because I have mostly the same feelings, it looks like a CS tumblr, a hodgepodge of random concepts from random areas. I took some similar notes in the past (but nowhere near the volume) and I benefited little from them. Today I think I would just go for large sheets of paper and basically prepare cheatsheets for myself from the areas I do some work in at least from time to time. You really have to put in the effort to organize it clearly and have some focus or learning-related note-taking becomes a waste of time in my experience. I do use Emacs with Org mode for notetaking daily though, for throwing together todo lists, organizing links, keep track of learning sessions etc.