I think that blogging would be hard to implement in schools mainly because the method is rather informal in terms of grading. It could be implemented as a side project or as an encouragement for the students to write, but not as a required method of teaching. In my opinion, because of the free -style of blogging, teachers would have a hard time trying to gauge the capability of the students. Especially for students who haven't mastered the maturity of writing in different forms ( switching between personal experience, fiction, factual and argumentative forms), blogging without fixed rules would not give them enough practice in disciplining their thought processes. If there are fixed rules for blogging, then it wouldn't be blogging or rather, fun blogging, would it?
Now, if you say that secondary school students would have already mastered the art of writing effective essays, I would beg to differ. I think that each individual differ in his maturity in writing, and he should be given the chance to sharpen his abilities in school. If she prefers to blog in her free time, then all the better.
For example, most people learn painting by drawing things in perspective (i.e. very close to real-life objects). I personally think that this gives them a structure to emulate and actually discipline their control of the brush and the painting that they produce. As people mature in their capability of painting, they are given the 'artistic freedom' to produce things that do not exist in real life... because essentially, art is... 'art'... not 'reality'.
As for writing from personal views and having peer reviews, I think that some teachers already implement this style of "free-writing," where you can write anything you want, as "journal-writing."
ACceptINg DiffEReNces == MAkiNg a DIfF3renC3