Todd Henry in his book The Accidental Creative: How to be Brilliant at a Moment's Notice (Portfolio/Penguin, 2011) uses the acronym FRESH for the elements of "creative rhythm": Focus, Relationships, Energy, Stimuli, Hours. His advice about note taking comes in a small section of the chapter on Stimuli. He recommends using notebooks with indexes, including a Stimuli index. He says, "Whenever you come across stimuli that you think would make good candidates for your Stimulus Queue, record them in the index in the front of your notebook." And "Without regular review, the practice of note taking is fairly useless." And "Over time you will begin to see patterns in your thoughts and preferences, and will likely gain at least a few ideas each week that otherwise would have been overlooked." Since Todd describes essentially the same effect as @Will but without mentioning a ZK, this "magic" or "power" seems to be a general feature of reviewing ideas or stimuli for creative ideation, not specific to a ZK. (@Will acknowledged this when he said, "Using the ZK method is one way of formalizing the continued review of ideas", not the only way.)