My journal is most useful when I'm writing fiction. In the middle of a furious writing session, I'll "take a break" by closing Scrivener and jumping into my journal. There I have a discussion with myself about what I'm writing, how I feel about it, the problems, etc. -- and as I write, I often reach a decision that makes me jump out of the journal and back into Scrivener, to proceed with the story. Journaling is a necessary part of my writing process.
But the sad fact is that I haven't written anything new in months. This fact upsets me. It's like "what's wrong with this picture?" But I have three "completed" books to get out the door. What else can I do but continue to finalize them? If I don't, they'll never see the light of day, nor a reader. In any case, I suspect the lack of fiction writing in my life is why I write less in my journal these days. I can't blame blogging, which seems to fit easily into my spare moments.
Anyone else do both? How does blogging affect your journaling? Are they related?