Linguistic Life is an ESL blog from a Michigan-based teacher.
There's an insightful reflection on using blogs with classes here
Here's an extract:
"My own class seems to be keeping up their blogs well. No doubt a large part of this is due to the fact that updating their blogs at least 3 times a week is 15% of their grade. However, I do not think that they would be so inclined to keep it up if I had simply told them it was a requirement and they had to do it. I spent a lot of time explaining why I thought this was an important thing for them to do, and how it could help their learning. I told them that writing on their blog forces them to think in English outside of class, but it lets them think, and write, about subjects that interest them. Constantly practicing their English writing will help their reading, speaking, listening, and grammar as well, because putting their English to use helps them remember vocabulary, and notice grammatical structures they have already learned."