Jonathan discussed using your own site as a private repository rather than just a place for public sharing citing the recent Day One privacy issue as a reason you might not want to trust third party apps.
I've never really been one for private journaling. When I did try Day One a while back it didn't stick probably because I post to the blog so regularly.
Posting private items to WordPress is something I've considered and dismissed before; however, Jonathan's microcast made me reconsider.
As I now post everything directly from Drafts it's simple to duplicate my "Post" action and change it to set the post status as Private. This means I don't have to adopt a different workflow for anything I might want to submit as anything approximating a journal entry.
Now, I don't know whether to exclude such entries from the blog even when logged in and set up a separate, private page. I could even go one stage further and create a custom post type.
Much to consider.