Teachers as Readers: Why do people journal?

I have been reading  The Secret Life of Bees by Sue Monk Kidd these last couple of weeks.  In addition, I have read various news articles.

For as long as I can remember, I have enjoyed keeping journals.  I can remember keeping different journals in classes thoughout my schooling.  In addition, I often would write in a diary or something similar.  Several years ago, I started blogging and that has become to way I frequently journal.  I enjoy being able to write down my thoughts and feelings, writing about things that are new and different for me, including photos or other small artifacts.  One of the things I most enjoy about journalling (is that a word?) is being able to look back on what I have written.  Whether it's a week later or several years later, I have always enjoyed being able to look back and see what was going on at a particular point in my life.  I can't ever remember keeping a journal to document what I'm reading (besides for classes of course!).  The times I do keep some sort of journal for a class, I have found that I do end up understanding the reading material better and also I usually think beyond the text.