Key Words — How Do Use Them

How do you use keywords? Here are a couple examples out of the Ulysses system. Other than noting in Ulysses key words can be auto added to the files list.(Library) I looking for different uses of key word in the apps of your choice.

Two examples below are my keywords and one I clipped from the Ulysses blog. That one is aimed more at fiction writers and mine aimed at file organization.