So, how do I employ it? One is to search on a subject I'm interested in or working on, ie to find notes, previous readings and writings, then add to these or go from there. Another is to keep various kinds of lists, (eg lists of ideas, things to read, etc). Otherwise the way your able to link things together with tags and other forms of linking is also pretty great - these are all features I will insist on when I move to something new, since I use tiddlywiki, which is a mostly dead project.
Anything with these features works like an external brain, allowing for recall, with just enough inefficient that you have to engage with the material, and possible mix some notes and facts together to hopefully inspire some new ideas.