There is one essential difference between blogging and journaling: the act of publication.
Both can be expressions of one’s self. Both can be brilliant. Both can be boring.
But, when you publish something, you are putting it out there into the world. Others can read your words, think about your words, and criticize your words.
The stakes are much higher, and because of this, the attention to detail—and the editing—become more important.
Writers publish.