I was thinking about journal writing again tonight.
Journaling is very different than blogging. When you write in a journal you can write secure in the knowledge that no one will read it unless you choose to let them. When you blog, complete strangers can read your every word. I believe there is a place for one or the other or both depending on what you need right now in your life.
Right now in my life I have a great many random thoughts rolling around in my head. There are things I want to research and learn more about. To me these things are natural to blog about. These things are mostly impersonal even though I do have opinions about them.
I love research. I love information. Gathering information on the net about random topics (although not really all that random to me) is an interesting hobby. You never know what you will find on the net.
If you love information like me then blogging and sharing the information seems like a natural next step. I think you can journal to a certain extent on your blog; as long as you keep in mind that the rest of the world is reading.
If you have personal issues that need attending to then journaling might be the better option. You can then share if and when you feel ready to.
Start writing and see where it takes you.