My wife has been going through old emails etc in an effort to construct her journal for the past few years. As she has been doing that, I have been going through old blog posts and seeing a little bit of my history for the last two years. The process has given me new perspective on the question of the intersection of blogs and journals.
Because of her efforts I recognize that journals have as much variety about them as I have long known that blogs have. My current position is that I will be blogging without regard to how it might serve as a journal. I can always go through later and decide about including any of my posts in a separate journal.