Following the "should not", here is the "should way" of using blogs in education by James Farmer. I echo strongly with James words:
Blogs are by no means the answer to everything, they are very strong alternative communication tools but if you want to build quizzes, run polls, have near-synchronous conversation, do listserv-y kind of discussion or strictly manage just about anything then you’ll probably want to look at another tool.
I would also caution the need of a balance between focussing on skills and concrete content. I am not discounting the importance and value of the ability to learn independently, literacy skills, information processing strategies, thinking skills,..... As a general practitioner in the field, we tend to describe learning situation and strategy in a generic term without reference to any content or specific subject matter.
It is true that information is exploding. Sometimes I question the value of the time and effort that I have put in during my years in learning Physics. By now, I don't think I would be able to derive any of those equations which I have spent so much time to understand and memorize. I don't even able to remember the exact spelling of the names of these equations.
However, is that experience totally wasted? Let's use thinking skill as an example. Learning to think is one thing. Applying the thinking skill in solving problems in a complex situation is quite different. Subject matter presents a complex context to exercise the thinking skill. I have forgotten most of the subject matter in Physics, but my basic training means I can tackle complex situation using mathematical skills when I need to.
Coming back to using blog, or for this matter any tool. Not only we should recognise that none of them is the only tool available, such tool should be used in a meaningful way in the context of some subject matter.
Here is another quote from James:
One of the worst things you can do is mandate posting on particular topics with particularly rigid frequency… you’ll over-assess & kill off exactly what blogs are good for: personal expression & exploration.
Within the context of your subject matter, you must create compelling reasons for the learners to create and maintain a blog. Note, mandating posts as assessment is NOT compelling reason in any stretch of imagination! Create and demonstrate a passion in the subject matter, engage and ensure the students themselves are engaged in constructive discussion with the use of blog in the context of your subject matter.
How to start one? Here is a suggestion.
There are many great insights that are counter-intuitive. These can be used as triggering points for heated discussion, via the blog, may be.
Blog is also well suited as a personal log of the learning journey. If you can show yours and some good examples, students can follow.
We don't want to see yet another teenage-blogger writing about fashion or gossip as part of their learning, do we?