Ancestor's Diaries/Journals May Support Genealogical Data

I am working on entering all my genealogy info on ancestry.com's Family Tree and have found a supporting source I had never thought of before. I am using Lillian's Diaries: Whispers of Galena's Past to add some of the "flesh" to people who I have statistic data on in my family tree and that Lillian has made diary entries of those same people that expand the person beyond just birth, death, marriage. etc. If you have the pleasure of having old letters or diaries/journals of your ancestors this might be a supporting source for your genealogy information.