In this article, Konrad Glogowski from Ontario explains his approach to evaluating student blogs.
I am posting it because some of my SUK4 students keep pestering me to grade their blogs.
I am hesitant to grade them however because I think ideally students should blog in order to find their voice and discover what blogging can do for them. If they are only doing it to get a grade, then I think they should reflect a bit more on what they stand to learn by taking their learning seriously. And keep in mind that ultimately anything they do they should be doing for themselves.
Here's a self-assessment scale he came up with that I like. He apparently has much younger students in an English class he teaches in Canada.
Here's a link to Konrad's blog