Now if I might generalize from my experience. . .
I had the opportunity, during the short time while I was working towards a PhD, to help teach a class, and more importantly to construct a blogging component for that class. In creating that component I faced the challenge of giving structure, for the purpose of making it possible to grade the assignment, to an activity which is best left unstructured. Perhaps it would be more accurate to say that, while blogging can benefit from structure - such as regular posting or a consistent topic or objective - it does not benefit from structure which is mandated by anyone other than the writer(s).
From what I have seen, the structure should be discovered during the early stages of creating the blog. The assignment I gave was first, one of three options for the students; second, required a minimum number of posts (20 if I remember correctly); third, had a minimum duration (8 weeks with at least two posts in each week out of a 12 week semester); and fourth, had to have an educational purpose in keeping with the course. I hoped this gave enough structure for the purposes of grading, was comparably rigorous to the other options, and was flexible enough to allow those who chose this option to find their own blogging rhythm.
As I observed the blogs of the students who opted for this assignment I noticed as they went through the growing pains of finding things to write about, discovered their voice, and explored their chosen educational purpose. I also saw that their thinking (as displayed in their posts) changed to be less inwardly focused and more focused on building on the thoughts expressed by others. That is one of the benefits of blogging. Over time the focus changes from a desire to create from the single source of the authors mind, to building on the work of other sources with similar topics.