You can create your own blog here, and then create categories, and just put your debt reduction journal entries into a category you create just for it.
For example, I have a blog, and I have two categories so far, although at this time, I have only put entries into one. One category is called Recipes, and the other is DIY/Decorating.
You could have one called Debt Snowball, and put your debt reduction related journals there, and have other categories for different things, like cooking, raising flying squirrels, or whatever.
Edited to add: If you don't want to share your blog, then you can set the permissions so no one but you and the admin/moderators can see it. I believe that would mean every blog post would be hidden and that you can't pick and choose which are visible, though, so don't do it if you ever want other people to see it.