Your personal book of knowledge (PBOK) is created for your future self.
At some point in the future, you are going to consume what you have created. You may consume it to make better decisions, to grow your knowledge, to understand yourself and your journey, and for many other reasons.
When you are journaling into your PBOK always keep your future self in mind. How will he find the information and in what circumstances will he be looking for the information?
Understanding your potential future self allows you to create organization, hashtags, and taxonomies that will assist your future self in extracting the value that is in your PBOK