“Significant” is an important word in doing scientific research, which means “important enough that you cannot ignore it”. For example, if you do scientific experiments, you need to compare results from two groups of data. You need to find out whether they have significant difference.
Here we want to borrow this concept and use it in our learning. So in learning/growth, Significant Experience means experiences that are constructive for your growth. They help you have a better understanding of things or yourself. Or they can be helpful to other. These experiences are big enough that you cannot ignore them. Other than Significant Experience, we have a lot of other random thoughts which really doesn’t help us much and should be filtered out.
Snippetbook is to record Significant Experiences mainly. Significant Experiences are the source of knowledge. Your brain processes the experiences in mainly two ways (greatly simplified): categorize and evaluate its weight. The constantly processed system is your knowledge, which makes your experiences easily accessible when situations come up.