I realize now where I went wrong.
Blogs aren't effective if they're being used in a way that transmits information in just one direction. That's where I failed. I thought a blog would be a good tool for me to get information to others. I didn't think about how the blog could be used to get information TO me FROM students and parents.
Re-thinking blogs over the past couple of weeks has given me some new ideas for how to use this tool in the classroom.
For my American history classroom, I can see blogs as a real asset in a couple of different ways. I start a lot of my classes with little thinking/writing prompts and sometimes end with a writing prompt for an exit ticket. Some of my kids have a difficult time completing this task in class. A blog would be a good place for me to post a discussion question or "critical thinking" question. Kids could have a set amount of time (maybe overnight, maybe a week) to respond to a comment and to others' comments. In this setting, the blog could possibly work the way discussion forums work.
I could also see the blog being an effective place to share news stories. Each week my students are encouraged to follow the latest news, to find a piece of positive news, and to find a piece of "weird" news. I ask for volunteers to share this information in class. With the blog, students could post the links directly.
I would like to use the blog for my English classes, as well. I can see the blog being a place to review books and share ideas about books. It would also be a place where I could elaborate on assignments and kids could bounce ideas off of each other.